build: use reusable-workflows [4]

Signed-off-by: Christian Kotzbauer <git@ckotzbauer.de>

.github/workflows/automerge.yml

@@ -1,16 +0,0 @@
-name: Merge PRs
-on:
-  schedule:
-    - cron: "0 */6 * * *"
-jobs:
-  automerge:
-    runs-on: ubuntu-latest
-    steps:
-      - name: automerge
-        uses: "pascalgn/automerge-action@8b306ad1983d0ea68c43e27101123e891ecff104"
-        env:
-          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
-          MERGE_LABELS: "approved,!work-in-progress,!hold"
-          MERGE_METHOD: "squash"
-          MERGE_DELETE_BRANCH: "true"
-          UPDATE_LABELS: "approved,!work-in-progress,!hold"