ci(github): add node version 16.x to CI workflow

Author: djcsdy

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: [10.x, 12.x, 14.x]
+        node-version: [10.x, 12.x, 14.x, 16.x]
     steps:
       - name: Find yarn cache
         id: find-yarn-cache