Update Node.js version requirement in README

Author: xiaolin

README.md

@@ -245,7 +245,7 @@ Each pull request (PR) should be specific and isolated to the issue you're tryin
 - Comment your code
 - Write [clean](https://github.com/ryanmcdermott/clean-code-javascript) code
 
-# Build the example locally (requires node >= 12.13)
+# Build the example locally (requires node >= 18.18)
 
 ```
 git clone https://github.com/xiaolin/react-image-gallery.git