Install llvm tools in github workflows

Author: mattia-moffa

.github/workflows/test-build.yml

@@ -75,7 +75,7 @@ jobs:
 
       - name: Install cross compilers
         run: |
-          sudo apt-get install -y gcc-arm-none-eabi gcc-aarch64-linux-gnu gcc-powerpc-linux-gnu gnu-efi
+          sudo apt-get install -y gcc-arm-none-eabi gcc-aarch64-linux-gnu gcc-powerpc-linux-gnu gnu-efi clang lld llvm
 
       - name: make clean
         run: |