Revise warning about Satchel v1 and mention Purse

Updated warning message regarding Satchel v1 and provided a link to the maintained alternative, Purse.

Signed-off-by: Ryan Luu <ryan.luu@ryanluu.dev>

Author: ryanlua

README.md

@@ -15,8 +15,8 @@
 
 </div>
 
-> [!TIP]
-> Want just the CoreGui backpack? Check out [Purse](https://github.com/ryanlua/purse), a sub-project of Satchel.
+> [!WARNING]
+> Satchel v1 is unmaintained to focus on v2 development. For a maintained alternative, see [Purse](https://purse.luau.page/).
 
 Satchel is a modern open-source alternative to Roblox's default backpack. Satchel aims to be more customizable and easier to use than the default backpack while still having a "vanilla" feel. Installation of Satchel is as simple as dropping the module into your game and setting up a few properties if you like to customize it. It has a familiar feel and structure as to the default backpack for ease of use for both developers and players.