[Github] only run dependabot action if debandabot made modifications

Author: tisoft

.github/workflows/dependabot_changelog.yml

@@ -15,7 +15,7 @@ permissions: write-all
 jobs:
   changelog:
     runs-on: ubuntu-latest
-    if: github.event.pull_request.user.login == 'dependabot[bot]'
+    if: github.actor == 'dependabot[bot]'
     steps:
       - uses: actions/checkout@v4
         with: