message: Fix typo in test.yaml
diff: @@ -509,7 +509,7 @@ jobs:
  build: linux-x64,
  os: ubuntu-18.04,
  target: x86_64-unknown-linux-gnu,
  - llvm_url: https://github.com/llvm/llvm-project/releases/download/llvmorg-13.0.0/clang+llvm-13.0.0-x86_64-linux-gnu-ubuntu-16.04.tar.xz
  + llvm_url: 'https://github.com/llvm/llvm-project/releases/download/llvmorg-13.0.0/clang+llvm-13.0.0-x86_64-linux-gnu-ubuntu-16.04.tar.xz'
  },
  {
  build: linux-x64,
  