add workflow to label cherry-pick versions on Pre-Commit-CI PRs

.github/labels.yaml

@@ -0,0 +1,8 @@
+---
+supported-branch-labels:
+  - 'CherryPick'
+  - '6.15.z'
+  - '6.14.z'
+  - '6.13.z'
+  - '6.12.z'
+

.github/workflows/pre_commit_labels.yml

@@ -0,0 +1,37 @@
+name: add cherry-pick version labels to pre-commit-ci pr's
+
+on:
+  pull_request_target:
+    types:
+      - opened
+      - ready_for_review
+      - reopened
+      - synchronize
+
+jobs:
+  add-labels:
+    runs-on: ubuntu-latest
+    if: github.actor == 'pre-commit-bot'
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Read labels from YAML
+        id: read-labels
+        run: |
+          LABELS=$(python3 -c "import yaml; print(' '.join(yaml.safe_load(open('./.github/labels.yaml'))['supported-branch-labels']))")
+          echo "LABELS=$LABELS" >> "$GITHUB_OUTPUT"
+
+      - name: apply cherry-pick version labels.
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.CHERRYPICK_PAT }}
+          script: |
+            const labels = '${{ steps.read-labels.outputs.LABELS }}';
+            const prNumber = '${{ github.event.number }}';
+            github.rest.issues.addLabels({
+              issue_number: prNumber,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              labels: labels.split(' ')
+            });