Update workflows to support macos (#2)

.github/workflows/main.yml

@@ -1,6 +1,6 @@
 # This starter workflow is for a CMake project running on a single platform. There is a different starter workflow if you need cross-platform coverage.
 # See: https://github.com/actions/starter-workflows/blob/main/ci/cmake-multi-platform.yml
-name: CMake on a single platform
+name: CMake on a ubuntu and macos
 
 on:
   push:
@@ -17,16 +17,23 @@ jobs:
     # 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: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        # https://github.com/actions/runner-images
+        os: [ubuntu-latest, ubuntu-20.04, macos-latest, macos-13]
 
     steps:
     - uses: actions/checkout@v3
 
-    - name: Update apt-get
-      run: sudo apt-get update
+    - name: Install libwebsockets on ubuntu
+      if: ${{ startsWith(matrix.os, 'ubuntu') }}
+      run: sudo apt-get update && sudo apt-get install -y libwebsockets-dev
 
-    - name: Install libwebsockets
-      run: sudo apt-get install libwebsockets-dev 
+    - name: Install libwebsockets on macos
+      if: ${{ startsWith(matrix.os, 'macos') }}
+      run: brew install libwebsockets
 
     - name: Configure CMake
       # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.