docs: add warning to README (#23)

Author: mikesmithgh

README.md

@@ -1,4 +1,12 @@
 # Better Git Prompt String
+
+> [!WARNING]\
+> 03/16/2024: bgps is actively undergoing a major v2 rewrite in ![go](https://img.shields.io/badge/Go-00ADD8?style=flat-square&logo=go&logoColor=white)
+>
+> This is a breaking change that will simplify and improve maintainability of bgps
+>
+> If you prefer to keep using legacy bgps, then use the tag [v1.0.0](https://github.com/mikesmithgh/bgps/releases/tag/v1.0.0)
+
 A better bash prompt for git. bgps provides a convenient way to customize
 the PS1 prompt and to determine information about the current git branch. 
 bgps can indicate if the branch has a clean or dirty working tree, whether