chore: rework release notes

reworks release note management based on github release note api

It does this in the following way:
1. Creates a tag on cutoff that is annotated
2. Calls the Github Release Note API together with a release note configuration file (very similar to drafter but allows us to specify a previous tag)
3. Generates the notes for the current branch based on the last found tag.

.github/config/release.yml

@@ -0,0 +1,28 @@
+changelog:
+  exclude:
+    labels:
+    - 'kind/skip-release-notes'
+    - 'wontfix'
+    - 'triage/wont-fix'
+    - 'triage/invalid'
+  categories:
+    - title: '‼️ Breaking Changes'
+      labels:
+        - 'breaking-change'
+    - title: '🚀 Features'
+      labels:
+        - 'kind/enhancement'
+        - 'feature'
+        - 'enhancement'
+    - title: '🐛 Bug Fixes'
+      labels:
+        - 'kind/bug'
+        - 'fix'
+        - 'bugfix'
+        - 'bug'
+    - title: '🧰 Maintenance'
+      labels:
+        - 'chore'
+    - title: '⬆️ Dependencies'
+      labels:
+        - 'dependencies'

.github/workflows/release-branch.yaml

@@ -80,7 +80,19 @@ jobs:
           ref: main
           fetch-depth: 0
           token: ${{ steps.generate_token.outputs.token }}
-
+      - name: Setup git config
+        run: |
+          git config user.name "GitHub Actions Bot"
+          git config user.email "<41898282+github-actions[bot]@users.noreply.github.com>"
+      # tag the cutoff point in main so that it can be used for release note generation
+      - name: Create Cutoff Tag in Main
+        run: |
+          set -e
+          tag="v${{ needs.cutoff-preconditions.outputs.minor }}"
+          msg="Cutoff for $tag"
+          git tag --annotate --message "${msg}" "$tag"
+          git push origin "$tag"
+      # create a new branch
       - name: Create Release Branch
         run: |
           set -e

.github/workflows/release-drafter.yaml

@@ -11,7 +11,7 @@ on:
 permissions:
   contents: read
   # The release-drafter action adds PR titles to the release notes once these are merged to main.
-  # A draft release is kept up-to-date listing the changes for the next minor release version.
+  # A draft release is kept up-to-date listing the changes for the next minor or patch release version for that branch.
 jobs:
   release-version:
     name: Release Version
@@ -31,12 +31,72 @@ jobs:
     env:
       RELEASE_VERSION: ${{ needs.release-version.outputs.version }}
     steps:
+      - name: Generate token
+        id: generate_token
+        uses: tibdex/github-app-token@v2
+        with:
+          app_id: ${{ secrets.OCMBOT_APP_ID }}
+          private_key: ${{ secrets.OCMBOT_PRIV_KEY }}
       - name: Checkout
         uses: actions/checkout@v4
-      - name: Drafter
-        uses: release-drafter/release-drafter@v6
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
-          tag: ${{env.RELEASE_VERSION }}
-          version: ${{env.RELEASE_VERSION }}
+          fetch-depth: 0
+          fetch-tags: true
+      - name: Setup Release with gh
+        env:
+          REF: ${{ github.ref }}
+          REPO: ${{ github.repository }}
+          GH_TOKEN: ${{ steps.generate_token.outputs.token }}
+        run: |
+          # generate the release notes based on the last previous tag.
+          # match only a valid semver tag.
+          # also do not match for the cutoff tag for the release branch.
+          # Example: If we are in releases/v0.18, we don't want to match v0.18 as the cutoff tag.
+          # Instead we want to match the one before that, which would be v0.17.
+          # That would generate us the notes from
+          # v0.17 to HEAD, which is what we want.
+          # 
+          # Implementors Note:
+          # ##*\/ removes everything before the last / in the ref,
+          # e.g. refs/heads/releases/v0.18 -> v0.18
+          previous_tag=$(git describe HEAD --abbrev=0 --tags --match "v*" --exclude "${REF##*\/}")
+          
+          if [[ -z $previous_tag ]]; then
+            echo "No previous tag found, cannot generate release notes"
+            exit 1
+          fi
+          
+          echo "Generating release notes for ${{env.RELEASE_VERSION}} starting from ${previous_tag} to HEAD"
+          
+          notes=$(\
+             gh api  \
+               --method POST \
+               -H "Accept: application/vnd.github+json" \
+               -H "X-GitHub-Api-Version: 2022-11-28" \
+               /repos/${REPO}/releases/generate-notes \
+               -f "tag_name=${{env.RELEASE_VERSION}}" \
+               -f "target_commitish=${{ github.ref }}" \
+               -f "previous_tag_name=${previous_tag}" \
+               -f "configuration_file_path=.github/config/release.yml" \
+               -q .body \
+             )
+          
+          echo "Release Notes generated for ${{env.RELEASE_VERSION}}:"
+          echo "${notes}"
+          
+          echo "Verifying if release ${{env.RELEASE_VERSION}} already exists"
+          if [[ -z $(gh release list -R ${REPO} --json name -q '.[] | select(.name == "${{env.RELEASE_VERSION}}")') ]]; then
+            echo "Release ${{env.RELEASE_VERSION}} does not exist yet, creating from scratch"
+            gh release create ${{env.RELEASE_VERSION}} \
+              --title "${{env.RELEASE_VERSION}}" \
+              --notes "${notes}" \
+              --draft \
+              --latest=false \
+              --target ${{ github.ref }} \
+              -R ${REPO}
+          else
+            echo "Release ${{env.RELEASE_VERSION}} already exists, updating existing..."
+            gh release edit ${{env.RELEASE_VERSION}} \
+              --notes "${notes}" \
+              -R ${REPO}
+          fi

.github/workflows/release.yaml

@@ -181,8 +181,27 @@ jobs:
         git commit -m "Release $RELEASE_VERSION"
         msg="Release ${{ env.RELEASE_VERSION }}"
         git tag --annotate --message "${msg}" ${{ env.RELEASE_VERSION }}
-        # push both the tag as well as a release branch with that tag.
+        # push the tag.
         git push origin ${{ env.RELEASE_VERSION }}
+    # If we encounter a release (i.e. NOT a candidate), we want to keep the tag in the release branch git history
+    # by merging it (without taking over its contents).
+    # This allows tools that rely on the latest tag (such as Release Note generators or git describe)
+    # to recognize the release as the latest version.
+    # We can then use this to generate release notes based on the previous tag.
+    # If we previously built a release candidate, the tag is not merged back.
+    # That results in the tag being "omitted" / not recognized while generating release notes.
+    # This is intended, because a candidate should never influence further release notes.
+    # Example:
+    # Branch releases/v0.19
+    # - Candidate Build v0.19.0-rc.1 => no merge, release notes based on original cutoff
+    # - Actual Build v0.19.0 => merge, release notes based on original cutoff
+    # - Candidate Build v0.19.1-rc.1 => no merge, release notes based on v0.19.0 due to previous merge
+    - name: Merge Release Tag back into release branch if not a release candidate
+      if: inputs.release_candidate == false
+      run: |
+        git checkout ${{ github.ref }}
+        git merge --strategy ours ${{ env.RELEASE_VERSION }}
+        git push origin ${{ github.ref }}
 
     - name: Create GPG Token file from Secret
       run: |