Add job for macos build

.github/workflows/build.yml

@@ -33,3 +33,14 @@ jobs:
         name: gazebo-plugin-binary
         path: gazebo/build/*.so
         retention-days: 1
+
+  build_simulator_macos:
+    runs-on: macos-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: Install Gazebo
+      run: brew tap osrf/simulation && brew install gazebo11
+    - name: Install SDL2
+      run: brew install sdl2
+    - name: Build simulator
+      run: make build_simulator