feat(workflow): update node version

Author: siyi98

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [ '12', '14', '16' ]
+        node: [ '14', '16' ]
     name: build steps
     steps:
       - uses: actions/checkout@v2