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

.github/workflows/clean.yml

@@ -0,0 +1,20 @@
+name: Clean untagged docker images from ghcr.io
+
+on:
+  release:
+    - published
+  workflow_dispatch:
+
+jobs:
+  clean:
+    name: Clean untagged docker images from ghcr.io
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+      - name: Run script
+        run: ./delete_ghcr_dangling_images.sh lowlighter metrics
+        working-directory: .github/workflows/maintenance
+        env:
+          GITHUB_TOKEN: ${{ secrets.GHCR_BOT_TOKEN }}

.github/workflows/maintenance.yml

@@ -1,46 +0,0 @@
-name: Maintenance 🧰
-
-on:
-  schedule:
-    - cron: "30 2 * * *"
-  workflow_dispatch:
-
-jobs:
-  workflow_removal:
-    runs-on: ubuntu-latest
-    name: Workflow cleanup 🧹👷‍♂️
-    # Errors will probably be caused by excesses in API quota, so we can safely continue.
-    # Remaining workflows will be removed in the next scheduled run.
-    continue-on-error: true
-    steps:
-      - name: Clone repository
-        uses: actions/checkout@v2.3.4
-
-      - name: Run deletion script 🗑
-        run: ./delete_workflows.sh lowlighter/metrics
-        working-directory: ./.github/workflows/maintenance
-        env:
-          GITHUB_TOKEN: ${{ github.token }}
-
-  dangling_images_removal:
-    runs-on: ubuntu-latest
-    name: Cleanup dangling images from GHCR 🧹📦
-    # Errors will probably be caused by excesses in API quota, so we can safely continue.
-    # Remaining workflows will be removed in the next scheduled run.
-    continue-on-error: true
-    # Pay attention that the org name is not necessary here, as gh will automatically take the one from the logged in user.
-    strategy:
-      fail-fast: false
-      matrix:
-        container:
-          - 'metrics'
-
-    steps:
-      - name: Clone repository
-        uses: actions/checkout@v2.3.4
-
-      - name: Run deletion script 🗑
-        run: ./delete_ghcr_dangling_images.sh lowlighter ${{ matrix.container }}
-        working-directory: ./.github/workflows/maintenance
-        env:
-          GITHUB_TOKEN: ${{ secrets.GHCR_BOT_TOKEN }}

.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 }}