Rework to use PyGitHub

https://github.com/PyGithub/PyGithub

```python
from github import Github

# Authentication is defined via github.Auth
from github import Auth

# using an access token
auth = Auth.Token("access_token")

# First create a Github instance:

# Public Web Github
g = Github(auth=auth)

# Then play with your Github objects:
for repo in g.get_user().get_repos():
    print(repo.name)
```