Added pr-closed.yml from ACCESS-OM2 without changes

.github/workflows/pr-closed.yml

@@ -0,0 +1,36 @@
+name: PR Closed Cleanup
+# Remove prereleases that were part of a closed PR, so we save space
+# on our deployment targets. If needed, one can still get the
+# spack.yaml as part of the closed PR and revive it themselves.
+on:
+  pull_request:
+    types:
+      - closed
+    branches:
+      - main
+      - backport/*.*
+    paths:
+      - config/**
+      - spack.yaml
+jobs:
+  setup:
+    name: Setup
+    runs-on: ubuntu-latest
+    outputs:
+      version-pattern: ${{ steps.version.outputs.pattern }}
+    steps:
+      - name: Version Pattern
+        id: version
+        # For example, `access-om3-pr12-*`
+        run: |
+          repo_name_lower=$(echo ${{ github.event.repository.name }} | tr [:upper:] [:lower:])
+          echo "pattern=${repo_name_lower}-pr${{ github.event.pull_request.number }}-*" >> $GITHUB_OUTPUT
+
+  undeploy-prereleases:
+    name: Undeploy Prereleases
+    needs:
+      - setup
+    uses: access-nri/build-cd/.github/workflows/undeploy-1-setup.yml@main
+    with:
+      version-pattern: ${{ needs.setup.outputs.version-pattern }}
+    secrets: inherit