ci: fixes to actions caches (#3970)

.github/workflows/cache-cleanup.yml

@@ -1,6 +1,6 @@
 name: CI Cache Cleanup
 on:
-  pull_request:
+  pull_request_target:
     types:
       - closed
 
@@ -22,7 +22,7 @@ jobs:
           echo "Deleting caches..."
           for cacheKey in $cacheKeysForPR
           do
-              gh actions-cache delete $cacheKey -R $REPO -B $BRANCH --confirm
+              gh actions-cache delete -R $REPO -B $BRANCH --confirm -- $cacheKey
           done
           echo "Done"
         env:

.github/workflows/ci.yml

@@ -526,6 +526,7 @@ jobs:
           workspaces:
             examples/maturin-starter
           save-if: ${{ github.event_name != 'merge_group' }}
+          key: ${{ matrix.target }}
       - name: Setup cross-compiler
         if: ${{ matrix.target == 'x86_64-pc-windows-gnu' }}
         run: sudo apt-get install -y mingw-w64 llvm