update node.js versions for CI from 12,14 to 14,16

Author: trusktr

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: [12.x, 14.x]
+        node-version: [14.x, 16.x]
         os: ['macos-latest', 'ubuntu-latest', 'windows-latest']
 
     steps: