ci: fix missing macOS testing

Close https://github.com/napi-rs/package-template/issues/329

.github/workflows/CI.yml

@@ -219,6 +219,8 @@ jobs:
         settings:
           - host: windows-latest
             target: x86_64-pc-windows-msvc
+          - host: macos-latest
+            target: x86_64-apple-darwin
         node:
           - '14'
           - '16'