chore(ci): Fix update-platform-branch to properly set platform.branch and update PR details (#342)

Updates the CI workflow that syncs platform.branch by ensuring PR bodies
include protocol release notes and that existing PRs get updated instead
of only creating new ones. Properly set the platform.branch.

Changes:
Add a step to fetch protocol release notes and write a pr_body.txt.
Add a step to edit an existing PR’s title/body when one already exists.
Move PR body generation earlier so both “edit PR” and “create PR” share
it.
Fix how were setting the platform.branch

#308

Author: elizabethhealy

.github/workflows/update-platform-branch.yaml

@@ -89,7 +89,7 @@ jobs:
         if: steps.check-update.outputs.no_updates != 'true'
         id: update-platform-branch
         run: |
-          find . -name "pom.xml" -exec sed -i.bak "s|<platform.branch>.*</platform.branch>|<platform.branch>${LATEST_TAG}</platform.branch>|g" {} \;
+          find . -name "pom.xml" -exec sed -i.bak "s|<platform.branch>.*</platform.branch>|<platform.branch>protocol/go/${LATEST_TAG}</platform.branch>|g" {} \;
           CHANGED_FILES=$(find . -name "pom.xml" -exec diff -u {} {}.bak \;)
           if [ -z "$CHANGED_FILES" ]; then
             echo "No changes detected in pom.xml files." | tee -a $GITHUB_STEP_SUMMARY
@@ -137,11 +137,11 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           BRANCH_NAME: update-platform-branch
 
-      - name: Create New PR
-        if: steps.check-pr.outputs.EXISTING_PR == '' && steps.update-platform-branch.outputs.changes == 'true'
+
+      - name: Get protocol release notes
+        if: steps.update-platform-branch.outputs.changes == 'true'
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          BRANCH_NAME: update-platform-branch
         run: |
           RELEASE_NOTES=$(gh release view protocol/go/$LATEST_TAG --repo opentdf/platform --json body --jq '.body')
           cat <<EOF > pr_body.txt
@@ -152,6 +152,23 @@ jobs:
           Release Notes:
           $RELEASE_NOTES
           EOF
+
+      - name: Update existing PR Title and description
+        if: steps.check-pr.outputs.EXISTING_PR != '' && steps.update-platform-branch.outputs.changes == 'true'
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          BRANCH_NAME: update-platform-branch
+        run: |
+          gh pr edit ${{ steps.check-pr.outputs.EXISTING_PR }} \
+            --title "fix(sdk): Updates to proto version $LATEST_TAG" \
+            --body-file pr_body.txt
+
+      - name: Create New PR
+        if: steps.check-pr.outputs.EXISTING_PR == '' && steps.update-platform-branch.outputs.changes == 'true'
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          BRANCH_NAME: update-platform-branch
+        run: |
           gh pr create \
             --title "fix(sdk): Updates to proto version $LATEST_TAG" \
             --body-file pr_body.txt \