Update pascalgn/automerge-action action to v0.16.4 (#54)

Author: renovate[bot]

.github/workflows/automerge.yaml

@@ -8,7 +8,7 @@ jobs:
     steps:
       - id: automerge
         name: automerge
-        uses: pascalgn/automerge-action@v0.16.3
+        uses: pascalgn/automerge-action@v0.16.4
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           MERGE_DELETE_BRANCH: true