John Liu

1. Fix the incorrect `pip install -e ...` command in [CONTRIBUTING.md](https://github.com/john-liu2/git-sim/blob/main/CONTRIBUTING.md) 2. Fixes #106 3. The screenshot: 

Doc, [CONTRIBUTING.md](https://github.com/john-liu2/git-sim/blob/main/CONTRIBUTING.md) has incorrect `pip install -e ...` command at `Step 6` in `Your first code contribution` section The bad one: ``` $ pip install -e .[dev] zsh: no matches...