Added ubuntu build actions

.github/workflows/ubuntu-build.yml

@@ -0,0 +1,20 @@
+name: ubuntu-build
+
+on:
+  push:
+    branches: [ main ]
+    
+  pull_request:
+    branches: [ main ]
+    
+jobs:    
+  ubuntu-build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: update apt
+      run: sudo apt-get update
+    - name: install raylib dependencies
+      run: sudo apt install libasound2-dev mesa-common-dev libx11-dev libxrandr-dev libxi-dev xorg-dev libgl1-mesa-dev libglu1-mesa-dev
+    - name: make
+      run: make