ci: merge removal of workflows with stale.yml and remove untagged docker images on release only

.github/workflows/stale.yml

@@ -1,4 +1,4 @@
-name: Stale issue and pull requests
+name: Stale issues, pull requests and workflow runs
 
 on:
   schedule:
@@ -12,7 +12,7 @@ jobs:
     steps:
       - uses: actions/stale@v3
         with:
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          repo-token: ${{ github.token }}
           stale-pr-message: This pull request seems to be inactive and will be automatically closed in a few days if it remains without any activity.
           days-before-pr-stale: 21
           days-before-pr-close: 3
@@ -34,3 +34,15 @@ jobs:
           pr-lock-inactive-days: 14
           pr-lock-reason: ""
           pr-lock-labels: ☑️ archived
+  workflows:
+    name: Remove expired workflow runs
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+      - name: Run script
+        run: ./delete_workflows.sh lowlighter/metrics
+        working-directory: .github/workflows/maintenance
+        env:
+          GITHUB_TOKEN: ${{ github.token }}