Add workflow to draft release notes

Author: timebertt

.github/workflows/release-notes.yaml

@@ -0,0 +1,32 @@
+name: release-notes
+
+on:
+  push:
+    branches:
+    - main
+    - release-notes
+
+jobs:
+  draft-release-notes:
+    runs-on: ubuntu-latest
+    steps:
+    - run: |
+        set -o errexit
+        set -o nounset
+        set -o pipefail
+        set -x
+        
+        latest_tag="$(gh api -H "Accept: application/vnd.github+json" -H "X-GitHub-Api-Version: 2022-11-28" /repos/timebertt/kubernetes-controller-sharding/releases/latest --jq .tag_name)"
+        
+        major="$(echo "$latest_tag" | cut -d. -f1)"
+        minor="$(echo "$latest_tag" | cut -d. -f2)"
+        new_tag="$major.$((minor+1)).0"
+        
+        if [ "$(gh release view "$new_tag" --json isDraft --jq .isDraft)" = true ] ; then
+          # clean up previous draft release
+          gh release delete -y "$new_tag"
+        fi
+        
+        gh release create "$new_tag" --draft --generate-notes --notes-start-tag="${latest_tag%.*}.0"
+      env:
+        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}