Install Vulkan SDK when running linux job

.github/workflows/ci.yml

@@ -8,6 +8,11 @@ jobs:
             CXX: g++-9
         steps:
         - uses: actions/checkout@v2
+        - name: Setup Vulkan SDK
+          run: wget -qO - https://packages.lunarg.com/lunarg-signing-key-pub.asc | sudo apt-key add -
+          run: sudo wget -qO /etc/apt/sources.list.d/lunarg-vulkan-focal.list https://packages.lunarg.com/vulkan/lunarg-vulkan-focal.list
+          run: sudo apt update
+          run: sudo apt install vulkan-sdk
         - name: Configure
           run: cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release
         - name: Build