chore: add cleaning workflow ci

.forgejo/workflows/clean-containers.yml

@@ -0,0 +1,25 @@
+name: Clean container registry
+on:
+  push:
+  workflow_dispatch:
+jobs:
+  clean:
+    runs-on: docker
+    strategy:
+      matrix:
+        box:
+          - "devbox"
+    steps:
+      - name: Get timestamp
+        id: timestamp
+        run: |
+          echo "year=$(date +'%Y-%m')" >> $GITHUB_OUTPUT
+          echo "current_month=$(date +'%Y-%m')" >> $GITHUB_OUTPUT
+      - uses: actions/delete-package-versions@v5
+        with:
+          package-name: ${{matrix.box}}
+          package-type: 'container'
+          min-version-to-keep: 3
+          # ignore latest and this month uploads
+          ignore-versions: '^(?:latest)$'
+          token: ${{ secrets.CONTAINER_REGISTRY_TOKEN }}