Add JBoss Log Manager to readme

Author: felixbarny

README.md

@@ -113,6 +113,7 @@ For nested structures consider prefixing with `custom.` to make sure you won't g
 - [Log4j2](log4j2-ecs-layout/README.md)
 - [Log4j](log4j-ecs-layout/README.md)
 - [java.util.logging](jul-ecs-formatter/README.md)
+- [JBoss Log Manager](jboss-logmanager-ecs-formatter/README.md)
 
 ### Step 2: Enable APM log correlation (optional)
 If you are using the Elastic APM Java agent,