add GAR cleanup job

.github/workflows/gar-cleanup.yml

@@ -0,0 +1,46 @@
+name: GAR Cleanup
+
+on:
+    schedule:
+        - cron: '30 6 * * *'
+    workflow_dispatch: {}
+    workflow_run:
+        workflows: ['Deploy']
+        types:
+            - completed
+
+jobs:
+    docker_cleanup:
+        name: Cleanup Deployed Images
+        runs-on: ubuntu-latest
+        needs:
+            - docker_sync
+        strategy:
+            matrix:
+                region: [us, europe, asia]
+        steps:
+            - name: Set up Cloud SDK
+              uses: google-github-actions/setup-gcloud@master
+              with:
+                  project_id: ${{ secrets.GCS_PROJECT_ID }}
+                  service_account_key: ${{ secrets.GCS_TF_KEY }}
+                  export_default_credentials: true
+
+            - name: Delete stale artifacts
+              run: |
+                  flags="--format=json --location=${{matrix.region}} --repository=roleypoly"
+
+                  packagesToPrune=$(gcloud artifacts packages list $flags 2>/dev/null | jq -r '.[].name')
+
+                  for package in $packagesToPrune; do
+                    tagsToKeep=$(gcloud artifacts tags list --package=$package $flags 2>/dev/null | jq -r '.[].version')
+                    versionsToCheck=$(gcloud artifacts versions list --package=$package $flags 2>/dev/null | jq -r '.[].name')
+
+                    for version in $versionsToCheck; do
+                      if [[ "$tagsToKeep" =~ .*"$version".* ]]; then
+                        continue
+                      fi
+
+                      gcloud artifacts versions delete $version --package=$package $flags 2>/dev/null
+                    done
+                  done