Add github CI action for macOS

.github/workflows/macos.yml

@@ -0,0 +1,21 @@
+name: macos
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: make
+      run: make
+    - name: install check
+      run: brew install check
+    - name: run tests
+      run: make test