fix: Correct Dependabot auto-merge condition to use pull request user login instead of actor.

Author: anyulled

.github/workflows/dependabot-auto-merge.yml

@@ -9,7 +9,7 @@ permissions:
 jobs:
   auto-merge:
     runs-on: ubuntu-latest
-    if: github.actor == 'dependabot[bot]'
+    if: github.event.pull_request.user.login == 'dependabot[bot]'
     steps:
       - name: Approve Dependabot PR
         run: gh pr review --approve "$PR_URL"