Doc/feature: Add fast `cargo install --git` method

[ackalker]

For those who have cargo available, please consider adding this fast install method, no need to clone the GitHub repository, builds and installs in a single step:

cargo install --git https://github.com/nashsu/AutoCLI

This will build autocli from GitHub, and install it in ~/.cargo/bin.
Make sure that ~/.cargo/bin is on $PATH and you're good to go.

❯ cargo install --list
autocli v0.3.8 (https://github.com/nashsu/AutoCLI#c0969e2c):
    autocli

❯ autocli --version
autocli 0.3.8