add node 18 to ci

Author: icebob

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       matrix:
         # node-version: [10.x, 12.x, 14.x, 15.x]
-        node-version: [10.x, 12.x, 14.x, 16.x]
+        node-version: [10.x, 12.x, 14.x, 16.x, 18.x]
       fail-fast: false
 
     steps: