feat: add renovate bot

Co-authored-by: Andreas Schmitz <schmitz@terrestris.de>
Co-authored-by: André Henn <henn@terrestris.de>

.github/renovate.json

@@ -0,0 +1,6 @@
+{
+    "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+    "extends": [
+        "config:best-practices"
+    ]
+}

.github/workflows/renovate.yml

@@ -0,0 +1,16 @@
+name: renovate
+on:
+  schedule:
+    - cron: '0 5 * * *' # every day at 5
+  workflow_dispatch:
+jobs:
+  renovate:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4.1.1
+      - name: Self-hosted Renovate
+        uses: renovatebot/github-action@v40.0.2
+        with:
+          configurationFile: .github/renovate.json
+          token: ${{ secrets.RENOVATE_TOKEN }}