Add compatibility notice CMK RAW 2.2.0b6 RHEL9

Author: filipnet

README.md

@@ -25,7 +25,8 @@ Telegram has long been one of my real-time communication media. It is obvious to
 ## COMPATIBILITY
 - Check_MK RAW version 1.6.0_p18 
 - Check_MK RAW version 2.0.0_p8 to 2.0.0p31
-- Check_MK RAW version 2.1.0p17
+- Check_MK RAW version 2.1.0p25
+- Check_MK RAW version 2.2.0b6 for RedHat/CentOS 9
 - Should also work with other versions of Check_MK
 
 ## EXAMPLE