Add reference to java 17 to README.md (#13765) (#13913)

Backport PR #13765 to 8.1 branch

(cherry picked from commit f1b17be)

Co-authored-by: Rob Bavey <rob.bavey@elastic.co>

README.md

@@ -44,7 +44,7 @@ Logstash core will continue to exist under this repository and all related issue
 
 ### Prerequisites
 
-* Install JDK version 11. Make sure to set the `JAVA_HOME` environment variable to the path to your JDK installation directory. For example `set JAVA_HOME=<JDK_PATH>`
+* Install JDK version 11 or 17. Make sure to set the `JAVA_HOME` environment variable to the path to your JDK installation directory. For example `set JAVA_HOME=<JDK_PATH>`
 * Install JRuby 9.2.x It is recommended to use a Ruby version manager such as [RVM](https://rvm.io/) or [rbenv](https://github.com/sstephenson/rbenv).
 * Install `rake` and `bundler` tool using `gem install rake` and `gem install bundler` respectively.