drop node 12 support

Author: blankdots

.github/workflows/eslint.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [ '12', '14' ]
+        node: ['14' ]
     name: Node ${{ matrix.node }} eslint check
     steps:
       - uses: actions/checkout@v2