allow and test against node 18 (#32)

Author: bradzacher

.github/workflows/node.js.yml

@@ -15,7 +15,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [12.x, 14.x, 16.x]
+        node-version: [12.x, 14.x, 16.x, 18.x]
         # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
 
     steps:

package.json

@@ -68,6 +68,6 @@
   },
   "typings": "dist/index.d.ts",
   "engines": {
-    "node": "12.x || 14.x || 16.x"
+    "node": "12.x || 14.x || 16.x || 18.x"
   }
 }