ci: unit test node 16 (#389)

- Unit test Node 16
- Use simple syntax like the docs: https://github.com/actions/setup-node

Author: grant

.github/workflows/unit.yml

@@ -8,7 +8,7 @@ jobs:
   test:
     strategy:
       matrix:
-        node-version: [10.x, 12.x, 14.x]
+        node-version: [10, 12, 14, 16]
         platform: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.platform }}
     steps: