Add llvm package to Github workflow (adds llvm-ar)

.github/workflows/ubuntu-build.yml

@@ -27,7 +27,7 @@ jobs:
     - name: Install Dependencies
       run: |
         sudo apt-get update
-        sudo apt-get -y install libboost-dev cython3 clang lld
+        sudo apt-get -y install libboost-dev cython3 clang lld llvm
 
     - name: Create Build Directory
       run: cmake -E make_directory ${{runner.workspace}}/build