add PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,16 @@
+### Proposed changes
+
+Describe the use case and detail of the change. If this PR addresses an issue on GitHub, make sure to include a link to
+that issue here in this description (not in the title of the PR).
+
+### Checklist
+
+Before creating a PR, run through this checklist and mark each as complete.
+
+- [ ] I have read the [CONTRIBUTING](https://github.com/nginxinc/nginx-prometheus-exporter/blob/main/CONTRIBUTING.md)
+      guide
+- [ ] I have proven my fix is effective or that my feature works
+- [ ] I have checked that all unit tests pass after adding my changes
+- [ ] I have ensured the README is up to date
+- [ ] I have rebased my branch onto main
+- [ ] I will ensure my PR is targeting the main branch and pulling from my branch on my own fork