README: Adjust required version numbers (#432)

macOS and Xcode 26 are both released now, no need to still list beta.

Author: dcantah

README.md

@@ -33,8 +33,8 @@ The API allows the runtime environment to be configured and containerized proces
 To build the Containerization package, you need:
 
 - Mac with Apple silicon
-- macOS 26 beta
-- Xcode 26 beta
+- macOS 26
+- Xcode 26
 
 Older versions of macOS are not supported.