fix(pre-commit-update): make idempotent

Author: tekumara

.github/workflows/pre-commit-update.yml

@@ -39,4 +39,8 @@ jobs:
         env:
           GH_TOKEN: ${{ github.token }}
         run: |
-          gh pr create --fill
+          if [[ -z "$(gh pr list --head bump-pre-commit-hooks --json number --jq '.[0].number')" ]]; then
+            gh pr create --fill
+          else
+            echo "PR already exists for bump-pre-commit-hooks branch"
+          fi