Prompt to 'git init' on repo create

Describe the feature or problem you'd like to solve

If you run glab repo create in a directory that isn't initialized with git the command fails:

→ glab repo create
fatal: not a git repository (or any of the parent directories): .git
git: exit status 128

It is required that the user first run git init before running glab repo create.

Propose a Solution

If the directory isn't git initialized, the user should be prompted whether glab should run git init before creating the repo

? Directory not git initialized. Run `git init`? [Y/N]

Additional context