config: remove renovate workflow

.github/workflows/renovate.yml

@@ -1,18 +0,0 @@
-name: Renovate
-
-on:
-  schedule:
-    - cron: 0 0 * * *
-  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:
-          token: ${{ secrets.RENOVATE_TOKEN }}
-          configurationFile: '.github/renovate.json'