Adding cleanup action on delete

.github/workflows/cleanup.yml

@@ -0,0 +1,24 @@
+name: Cleanup images and environments
+
+on:
+  - delete
+
+# Enables BuildKit
+env:
+  DOCKER_BUILDKIT: 1
+
+jobs:
+
+  delete_namespace:
+    runs-on: ubuntu-latest
+
+    steps:
+      # Create a slugified value of the branch
+      - uses: rlespinasse/github-slug-action@1.1.0
+
+      - name: Cleanup
+        uses: thecodingmachine/deeployer-cleanup-action@master
+        env:
+          KUBE_CONFIG_FILE: ${{ secrets.KUBE_CONFIG_FILE }}
+        with:
+          namespace: workadventure-${{ env.GITHUB_REF_SLUG }}