add auto approval for dependabot PRs

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

.github/workflow/autoApproveDependabot.yml

@@ -0,0 +1,13 @@
+name: Auto approve
+on:
+    pull_request_target:
+        branches: [ master, stable-* ]
+
+jobs:
+    auto-approve:
+        runs-on: ubuntu-latest
+        steps:
+            -   uses: hmarr/auto-approve-action@v2.0.0
+                if: github.actor == 'dependabot[bot]' || github.actor == 'dependabot-preview[bot]'
+                with:
+                    github-token: "${{ secrets.GITHUB_TOKEN }}"