Add action to clean up untagged (non-multiarch) images from GHCR

Signed-off-by: Adam Warner <me@adamwarner.co.uk>

.github/workflows/housekeeping.yml

@@ -0,0 +1,28 @@
+name: housekeeping
+on:
+  workflow_dispatch:
+
+jobs:
+    housekeeping:
+        runs-on: ubuntu-latest
+        steps:
+            -
+                name: Set up Docker Buildx
+                uses: docker/setup-buildx-action@v2
+            -
+                name: Login to GitHub Container Registry with PAT_TOKEN
+                uses: docker/login-action@v2
+                with:
+                    registry: ghcr.io
+                    username: ${{ github.actor }}
+                    password: ${{ secrets.PAT_TOKEN }}
+            -
+                name: Delete all containers from repository without tags
+                uses: Chizkiyahu/delete-untagged-ghcr-action@v2
+                with:
+                    token: ${{ secrets.PAT_TOKEN }}
+                    repository_owner: ${{ github.repository_owner }}
+                    repository: ${{ github.repository }}
+                    untagged_only: true
+                    owner_type: org # or user
+                    except_untagged_multiplatform: true