Add initial CI for Mac

.github/workflows/build_mac.yml

@@ -0,0 +1,34 @@
+name: Build macOS
+on: [push, pull_request]
+
+jobs:
+
+  # Editor
+  editor-mac:
+    name: Editor (Mac, Development x64)
+    runs-on: "macos-latest"
+    steps:
+    - name: Checkout repo
+      uses: actions/checkout@v2
+    - name: Checkout LFS
+      run: |
+        git lfs version
+        git lfs pull
+    - name: Build
+      run: |
+        ./Development/Scripts/Mac/CallBuildTool.sh -build -log -arch=x64 -platform=Mac -configuration=Development -buildtargets=FlaxEditor
+
+  # Game
+  game-mac:
+    name: Game (Mac, Release x64)
+    runs-on: "macos-latest"
+    steps:
+    - name: Checkout repo
+      uses: actions/checkout@v2
+    - name: Checkout LFS
+      run: |
+        git lfs version
+        git lfs pull
+    - name: Build
+      run: |
+        ./Development/Scripts/Mac/CallBuildTool.sh -build -log -arch=x64 -platform=Mac -configuration=Release -buildtargets=FlaxGame