docs: update README.md

Author: iluwatar

README.md

@@ -7,7 +7,7 @@ language: en
 
 ## 30 Seconds of Java - Essential Code Snippets Library for Java Developers
 
-Inspired by [30 seconds of code](https://github.com/Chalarangelo/30-seconds-of-code), this is a collection of reusable, tested, and copy-pasteable Java 17 compatible code snippets that you can understand in 30 seconds or less. If you're interested in contributing to this library, please see the [contribution guidelines](https://github.com/iluwatar/30-seconds-of-java/blob/master/CONTRIBUTE.md).
+Inspired by [30 seconds of code](https://github.com/Chalarangelo/30-seconds-of-code), this is a collection of reusable, tested, and copy-pasteable Java 21 compatible code snippets that you can understand in 30 seconds or less. If you're interested in contributing to this library, please see the [contribution guidelines](https://github.com/iluwatar/30-seconds-of-java/blob/master/CONTRIBUTE.md).
 
 ## Algorithm
 

localization/es/README.md

@@ -1,7 +1,7 @@
 # 30 Segundos de Java
 
 Inspirada en [30 seconds of code](https://github.com/Chalarangelo/30-seconds-of-code), esta es una colección de
-fragmentos de código reutilizables, probados y compatibles con Java 17 que se pueden copiar y pegar en 30 segundos o
+fragmentos de código reutilizables, probados y compatibles con Java 21 que se pueden copiar y pegar en 30 segundos o
 menos. Si está interesado en contribuir a esta biblioteca, consulte las [instrucciones](https://github.com/iluwatar/30-seconds-of-java/blob/master/CONTRIBUTE.md).
 
 ## Algoritmos