Add back in llvm checkout

Author: tstellar

.github/workflows/release-binaries.yml

@@ -194,6 +194,11 @@ jobs:
     runs-on: ${{ needs.prepare.outputs.build-runs-on }}
     steps:
 
+    - name: Checkout LLVM
+      uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      with:
+        ref: ${{ needs.prepare.outputs.ref }}
+
     - name: Install Ninja
       uses: llvm/actions/install-ninja@a1ea791b03c8e61f53a0e66f2f73db283aa0f01e # main