github-actions: exclude docker build for forked PRs or dependabot

Author: v1v

.github/workflows/ci.yml

@@ -40,6 +40,8 @@ jobs:
     - run: pip-licenses
 
   operator-image-buildable:
+    # If no PR event or if a PR event that's caused by a non-fork and non dependabot actor
+    if: github.event_name != 'pull_request' || ( github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork == false && github.actor != 'dependabot[bot]' )
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4