chore: run cache deletion on pr closed (#21)

Author: pranc1ngpegasus

.github/workflows/cache.yaml

@@ -1,7 +1,8 @@
 name: Cache
 on:
-  schedule:
-    - cron: "0 0 * * *"
+  pull_request:
+    types:
+      - closed
   workflow_dispatch:
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}-cache