ci: add node-14.x to workflow (#117)

Author: erisu

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        node-version: [10.x, 12.x]
+        node-version: [10.x, 12.x, 14.x]
         os: [ubuntu-latest, macos-latest]
 
     steps: