Function init_git_repo 

fn init_git_repo(
    git: Git<'_>,
    commit: bool,
    use_parent_git: bool,
    vyper: bool,
) -> Result<()>

Initialises root as a git repository, if it isn’t one already, unless ‘use_parent_git’ is true.

Creates .gitignore and .github/workflows/test.yml, if they don’t exist already.

Commits everything in root if commit is true.