Bump minimum supported Node.js version to 14.0.0

Latest version of ESLint no longer supports v12.0.0 that went EOL
in April, 2022

Add Node.js 18.0.0 to CI

.github/workflows/node.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-v: [12.x, 14.x, 16.x]
+        node-v: [14.x, 16.x, 18.x]
     steps:
       - name: Checkout
         uses: actions/checkout@v2

package.json

@@ -35,7 +35,7 @@
     "url": "http://github.com/wikimedia/language-data/issues"
   },
   "engine": {
-    "node": ">=12.0.0"
+    "node": ">=14.0.0"
   },
   "license": "GPL-2.0-or-later",
   "scripts": {