ci: stop testing against NodeJS v14, v16

.github/workflows/test.yml

@@ -14,7 +14,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
-          node-version: 16
+          node-version: 18
           cache: npm
       - name: Install
         run: npm ci

lib/create-test-action.js

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node_version: ["14", "16", "18"]
+        node_version: ["18", "20"]
 
     steps:
       - uses: actions/checkout@v3

package.json

@@ -37,6 +37,6 @@
     ]
   },
   "engines": {
-    "node": ">= 14"
+    "node": ">= 18"
   }
 }