Chore: Update README.md to mention git-lfs requirement (#698)

The cline repo will fail to clone without git-lfs, as demo.gif is a pointer. This leaves the user with a incomplete cloned repository.

README.md

@@ -104,7 +104,7 @@ To contribute to the project, start by exploring [open issues](https://github.co
 <details>
 <summary>Local Development Instructions</summary>
 
-1. Clone the repository:
+1. Clone the repository *(Requires [git-lfs](https://git-lfs.com/))*:
     ```bash
     git clone https://github.com/cline/cline.git
     ```