build: add macos-latest to ci matrix (libuv#3331)

Co-authored-by: Jameson Nash <vtjnash@gmail.com>
Fixes: libuv#3325

.github/workflows/CI.yml

@@ -47,6 +47,25 @@ jobs:
           $ANDROID_HOME/cmake/3.10.2.4988404/bin/cmake -DCMAKE_TOOLCHAIN_FILE=$ANDROID_HOME/ndk/20.0.5594570/build/cmake/android.toolchain.cmake -DCMAKE_BUILD_TYPE=Release -DANDROID_ABI="arm64-v8a" -DANDROID_PLATFORM=android-21 ..
           $ANDROID_HOME/cmake/3.10.2.4988404/bin/cmake --build .
 
+  build-macos:
+    runs-on: macos-10.15
+    steps:
+      - uses: actions/checkout@v2
+      - name: Envinfo
+        run: npx envinfo
+      - name: Setup
+        run: |
+          brew install ninja
+      - name: Build
+        run: |
+          mkdir build
+          cd build && cmake .. -DBUILD_TESTING=ON -G Ninja
+          cmake --build .
+          ls -lh
+      - name: Test
+        run: |
+          cd build && ctest -V
+
   build-cross-qemu:
     runs-on: ubuntu-latest
     name: build-cross-qemu-${{ matrix.config.target }}