ci: Run test on node 12 & 14

Author: t-ho

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [12.x]
+        node-version: [12.x, 14.x]
 
     steps:
       - uses: actions/checkout@v2