Use user.login to identify whether the PR is from dependabot

Author: Oleg

.github/workflows/build.yml

@@ -186,7 +186,7 @@ jobs:
     needs: build
     runs-on: ubuntu-latest
 
-    if: (!cancelled() && github.event_name == 'pull_request' && github.actor == 'dependabot[bot]')
+    if: (!cancelled() && github.event_name == 'pull_request' && github.event.pull_request.user.login == 'dependabot[bot]')
 
     permissions:
       contents: write