chore(ci): clean up actions cache when closing a pr

Author: jeboehm

.github/workflows/cleanup-caches.yml

@@ -0,0 +1,17 @@
+name: Cleanup branch caches
+on:
+  pull_request:
+    types:
+      - closed
+jobs:
+  cleanup:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Delete all caches for the PR ref
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_REPO: ${{ github.repository }}
+        run: |
+          gh cache delete --all \
+            --ref refs/pull/${{ github.event.number }}/merge \
+            --succeed-on-no-caches