Clarified breaking change in release 1.0 changelog (#1047)

Author: ahmedetefy

CHANGELOG.md

@@ -22,9 +22,9 @@ A major release `N` implies the previous release `N-1` will no longer receive up
 
 ## 1.0.0
 
-This release contains breaking changes
+This release contains a breaking change
 
-- Feat: Moved `auto_session_tracking` experimental flag to a proper option and removed `session_mode`, hence enabling release health by default #994
+- **BREAKING CHANGE**: Feat: Moved `auto_session_tracking` experimental flag to a proper option and removed explicitly setting experimental `session_mode` in favor of auto detecting its value, hence enabling release health by default #994
 - Fixed Django transaction name by setting the name to  `request.path_info` rather than `request.path`
 - Fix for tracing by getting HTTP headers from span rather than transaction when possible #1035
 - Fix for Flask transactions missing request body in non errored transactions #1034