ci: Run tests on node 18

Author: relekang

.github/workflows/main.yml

@@ -8,7 +8,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [14.x, 16.x, 18.x]
+        node-version: [18.x]
 
     steps:
     - uses: actions/checkout@v2