have pre-release workflow update CHANGELOG

Author: ezhang6811

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

@@ -94,6 +94,14 @@ jobs:
           git commit -am "Update version to ${VERSION}"
           git push origin "v${VERSION}_release"
 
+      - name: Update CHANGELOG for release
+        run: |
+          # Replace "## Unreleased" with "## ${VERSION} - $(date +%Y-%m-%d)"
+          sed -i "s/## Unreleased/## ${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:
           GITHUB_TOKEN: ${{ env.BOT_TOKEN_GITHUB_RW_PATOKEN }}
@@ -103,4 +111,24 @@ jobs:
           
           By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice." \
                        --head v${{ github.event.inputs.version }}_release \
-                       --base release/v${MAJOR_MINOR}.x
+                       --base release/v${MAJOR_MINOR}.x
+
+      - name: Create pull request against main for CHANGELOG
+        env:
+          GITHUB_TOKEN: ${{ env.BOT_TOKEN_GITHUB_RW_PATOKEN }}
+        run: |
+          # Create branch for main PR
+          git checkout -b "v${VERSION}_changelog_main"
+          
+          # Update CHANGELOG for main (keep Unreleased + add release entry)
+          sed -i "s/## Unreleased/## Unreleased\n\n## ${VERSION} - $(date +%Y-%m-%d)/" CHANGELOG.md
+          git add CHANGELOG.md
+          git commit -m "Add ${VERSION} to CHANGELOG"
+          git push origin "v${VERSION}_changelog_main"
+          
+          gh pr create --title "Add ${VERSION} to CHANGELOG" \
+                       --body "This PR adds the ${VERSION} release entry to CHANGELOG.md.
+          
+          By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice." \
+                       --head v${{ github.event.inputs.version }}_changelog_main \
+                       --base main