Update supported Node.js versions (#105)

* Update Node.js versions in CI workflow

Current and LTS releases: v14, v16, v18

* Add `engines` field to package.json

* Add 'Requirements' section to the README

Author: simonplend

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [10.x, 12.x, 14.x, 15.x, 16.x]
+        node-version: [14.x, 16.x, 18.x]
 
     steps:
     - uses: actions/checkout@v2

README.md

@@ -18,7 +18,11 @@ requests against JSON schemas.
 - **Error Messaging** - Ajv provides you with rich error objects that can easily be transformed into human-readable format.
 - **Documentation** - Creating a JSON Schema is another way of documenting your application.
 
-## Install
+## Requirements
+
+- [Node.js](https://nodejs.org/en/download/) >= v14
+
+## Installation
 
 ```sh
 npm install express-json-validator-middleware

package.json

@@ -45,6 +45,9 @@
 		"@types/json-schema": "^7.0.4",
 		"ajv": "^8.8.2"
 	},
+	"engines": {
+		"node": ">=14"
+	},
 	"husky": {
 		"hooks": {
 			"pre-commit": "lint-staged"