Add Node.js 14.x to test matrix

Author: jbergstroem

.github/workflows/nodejs.yml

@@ -15,7 +15,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [8.x, 10.x, 12.x]
+        node-version: [8.x, 10.x, 12.x, 14.x]
 
     steps:
       - uses: actions/checkout@v2