try something else

.github/workflows/build-docs.yml

@@ -36,7 +36,7 @@ jobs:
           git checkout gh-pages || git checkout --orphan gh-pages
           git pull origin gh-pages || true
           rm -rf *
-          mv -f ./docs/_build/html/* .
+          mv -f ../${{ github.workspace }}/docs/_build/html/* .
           touch .nojekyll
           git add .
           git commit -m "Deploy documentation from GitHub Actions"