chore(renovate): Migrate to self-hosted Renovate.

This reverts commit 6afc8f6.

Author: octo

.github/workflows/renovate.yml

@@ -0,0 +1,26 @@
+name: Renovate
+on:
+  schedule:
+    # Run every Monday at 2:00 AM
+    - cron: '0 2 * * 1'
+  workflow_dispatch: # Allow manual triggering
+
+jobs:
+  renovate:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+      issues: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Self-hosted Renovate
+        uses: renovatebot/github-action@v39.0.5
+        with:
+          token: ${{ secrets.RENOVATE_TOKEN }}
+          configurationFile: .renovate.json
+        env:
+          LOG_LEVEL: 'info'
+          RENOVATE_REPOSITORIES: ${{ github.repository }}