update node versions to test with

to '14', '16', '18'

.github/workflows/nodejs.yml

@@ -31,7 +31,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: ['12', '14']
+        node-version: ['14', '16', '18']
 
     steps:
     - uses: actions/checkout@v2