Update README.md

Author: thomasrockhu-codecov

README.md

@@ -11,9 +11,10 @@
 ### Migration Guide
 The `v5` release also coincides with the opt-out feature for tokens for public repositories. In the repository settings page in codecov.io, you can set the ability for Codecov to receive a coverage report from ANY souce. This will allow contributors or other members of a repository to upload without needing access to the Codecov token.
 
-**The following arguments have been changed**
-- `file` (this has been deprecated in favor of `files`)
-- `plugin` (this has been deprecated in favor of `plugins`)
+> [!WARNING]  
+> **The following arguments have been changed**
+> - `file` (this has been deprecated in favor of `files`)
+> - `plugin` (this has been deprecated in favor of `plugins`)
   
 The following arguments have been added: