update pre and post release workflows

Author: ezhang6811

.github/workflows/post-release-version-bump.yml

@@ -6,6 +6,10 @@ on:
       version:
         description: 'Version number (e.g., 1.0.1)'
         required: true
+      is_patch:
+        description: 'Is this a patch? (true or false)'
+        required: true
+        default: 'false'
 
 env:
   AWS_DEFAULT_REGION: us-east-1
@@ -109,6 +113,16 @@ jobs:
           VERSION="${{ github.event.inputs.version }}"
           npm install
           sed -i  "s|\(/aws-observability/adot-autoinstrumentation-node:\)v[0-9]\+\.[0-9]\+\.[0-9]\+|\1v${{github.event.inputs.version}}|g" .github/workflows/daily-scan.yml
+
+          # for patch releases, avoid merge conflict by manually resolving CHANGELOG with main
+          if [[ "${{ github.event.inputs.is_patch }}" == "true" ]]; then            
+            git fetch origin main
+            git show origin/main:CHANGELOG.md | sed -n '/## Unreleased/,/^## v[0-9]/p' | sed '$d' | tail -n +2 | sed '/^$/d' > /tmp/unreleased_content.txt
+                        
+            # Insert the content right after the existing "## Unreleased" header
+            sed -i '/## Unreleased/r /tmp/unreleased_content.txt' CHANGELOG.md
+          fi
+          
           git add .
           git status
           git commit -m "Prepare main for next development cycle: Update version to $DEV_VERSION"

.github/workflows/pre-release-prepare.yml

@@ -102,6 +102,13 @@ jobs:
           npm install          
           git commit -am "Update version to ${VERSION}"
           git push origin "v${VERSION}_release"
+      
+      - name: Update CHANGELOG for release
+        run: |
+          sed -i "s/## Unreleased/## Unreleased\n\n## v${VERSION} - $(date +%Y-%m-%d)/" CHANGELOG.md
+          git add CHANGELOG.md
+          git commit -m "Update CHANGELOG for version ${VERSION}"
+          git push origin "v${VERSION}_release"
 
       - name: Create pull request against the release branch
         env: