Testing github action

Travis is no longer free. So need to test alternatives.

.github/workflows/cmake.yml

@@ -0,0 +1,34 @@
+name: CMake
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+env:
+  BUILD_TYPE: Release
+
+jobs:
+  build:
+    # The CMake configure and build commands are platform agnostic and should work equally well on Windows or Mac.
+    # You can convert this to a matrix build if you need cross-platform coverage.
+    # See: https://docs.github.com/en/free-pro-team@latest/actions/learn-github-actions/managing-complex-workflows#using-a-build-matrix
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ ubuntu-18.04, ubuntu-20.04, ubuntu-latest, macos-latest ]
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Install needed dependencies
+      run: sudo apt install xorg-dev libglu1-mesa-dev
+      if: ${{ matrix.os }} != "macos-latest"
+
+    - name: Configure CMake
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+
+    - name: Build
+      run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}}
+