Add Branch Specification for Plugin Installation

[tareknaser]

Description:

The objective of this enhancement is to let users specify a branch when installing plugins using coffee.

It is important to note that this proposal assumes the presence of only one plugin in each remote repository.

Goal:

• Allow users to install a plugin from a specific branch using the command:

coffee install <plugin_name> --branch <branch_name>`

Existing Features:

• The repository struct already includes a branch field.
• A function, fast_forward(path: &str, branch: &str) -> Result<UpgradeStatus, CoffeeError>, is available to facilitate fast-forwarding to a specified branch.