Use github.ref_name for checkout

Author: hamishmack

Diff for: .github/workflows/upload-artifacts.yml

@@ -16,6 +16,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          ref: ${{ github.ref_name }}
 
       - name: Install Nix with good defaults
         uses: input-output-hk/install-nix-action@v20