Add node 18 to test runner

Author: fiznool

.github/workflows/nodejs.yml

@@ -12,7 +12,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [10.x, 12.x, 14.x, 16.x]
+        node-version: [10.x, 12.x, 14.x, 16.x, 18.x]
 
     steps:
       - uses: actions/checkout@v2