add renovate pipeline

.forgejo/workflows/renovate.yml

@@ -0,0 +1,23 @@
+name: Renovate
+
+on:
+  schedule:
+    - cron: "20 * * * *"
+
+jobs:
+  renovate:
+    runs-on: docker
+    container: renovate/renovate@sha256:52ab6e316c70f51f198cfce709d3a56bd0c2025a1fe380d642c6d8da224ef012
+    env:
+      RENOVATE_TOKEN: ${{ secrets.RENOVATE_TOKEN }}
+      GITHUB_COM_TOKEN: ${{ secrets.GH_NOPRIV_TOKEN }}
+      RENOVATE_GIT_PRIVATE_KEY: ${{ secrets.JOHNNY5_GPG_PRIVKEY }}
+      RENOVATE_PLATFORM: gitea
+      RENOVATE_ENDPOINT: ${{ github.server_url }}
+      RENOVATE_GIT_AUTHOR: "Johnny5 <bot@snaile.de>"
+
+    steps:
+      - uses: https://code.forgejo.org/actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4.1.6
+
+      - name: Renovate
+        run: renovate ${{ github.repository }}