gha: include tightening of rules in action

Signed-off-by: Vitor Bandeira <[email protected]>

Author: vvbandeira

.github/workflows/github-actions-cron-update-OR.yml

@@ -30,6 +30,9 @@ jobs:
           signoff: true
           delete-branch: true
           title: 'Update OpenROAD submodule'
+          body: |
+            Automated action to update tools/OpenROAD submodule and tighten CI rule checking.
+            [ci:rules-tighten]
           reviewers: |
             vvbandeira
             maliberty