Auto approve/merge also on stable branches

Signed-off-by: Julius Härtl <jus@bitgrid.net>

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

@@ -1,5 +1,9 @@
 name: Dependabot
-on: pull_request_target
+on:
+  pull_request_target:
+     branches:
+      - master
+      - stable*
 
 jobs:
   auto-merge:
@@ -7,15 +11,13 @@ jobs:
     steps:
       # Default github action approve
       - uses: hmarr/auto-approve-action@v2.0.0
-        if: github.ref == 'refs/heads/master' &&
-            (github.actor == 'dependabot[bot]' || github.actor == 'dependabot-preview[bot]')
+        if: (github.actor == 'dependabot[bot]' || github.actor == 'dependabot-preview[bot]')
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
 
       # Nextcloud bot approve and merge request
       - uses: ahmadnassri/action-dependabot-auto-merge@v2
-        if: github.ref == 'refs/heads/master' &&
-            (github.actor == 'dependabot[bot]' || github.actor == 'dependabot-preview[bot]')
+        if: (github.actor == 'dependabot[bot]' || github.actor == 'dependabot-preview[bot]')
         with:
           target: minor
           github-token: ${{ secrets.DEPENDABOT_AUTOMERGE_TOKEN }}