Add update-libs flow

.github/workflows/update-libs.yaml

@@ -0,0 +1,25 @@
+name: Auto-update Charm Libraries
+on:
+  # Manual trigger
+  workflow_dispatch:
+  # Check regularly the upstream every four hours
+  schedule:
+    - cron: "0 0,4,8,12,16,20 * * *"
+
+jobs:
+  update-lib:
+    name: Check libraries
+    uses: canonical/observability/.github/workflows/charm-update-libs.yaml@main
+    secrets: inherit
+
+  detect-open-prs:
+    name: Check open library updates PRs
+    needs: update-lib
+    runs-on: ubuntu-24.04
+    outputs:
+      open_prs: ${{ steps.open-prs.outputs.open_prs }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0