Missing set permission for collaborators

[NargiT]

Missing parameter to handle permission for users

https://developer.github.com/v3/repos/collaborators/#add-user-as-a-collaborator

Version Information

Please provide:

• The version of Python you're using 3.6

• The version of pip you used to install github3.py 19.1.1

• The version of github3.py, requests, uritemplate, and dateutil installed github3.py==1.3.0

  • jwcrypto [required: >=0.5.0, installed: 0.6.0]
    • cryptography [required: >=1.5, installed: 2.7]
      • asn1crypto [required: >=0.21.0, installed: 0.24.0]
      • cffi [required: >=1.8,!=1.11.3, installed: 1.12.3]
        • pycparser [required: Any, installed: 2.19]
      • six [required: >=1.4.1, installed: 1.12.0]
  • python-dateutil [required: >=2.6.0, installed: 2.8.0]
    • six [required: >=1.5, installed: 1.12.0]
  • requests [required: >=2.18, installed: 2.22.0]
    • certifi [required: >=2017.4.17, installed: 2019.6.16]
    • chardet [required: >=3.0.2,<3.1.0, installed: 3.0.4]
    • idna [required: >=2.5,<2.9, installed: 2.8]
    • urllib3 [required: >=1.21.1,<1.26,!=1.25.1,!=1.25.0, installed: 1.25.3]
  • uritemplate [required: >=3.0.0, installed: 3.0.0]

Minimum Reproducible Example

Missing permission as a put payload

def add_collaborator(self, username):
       """Add ``username`` as a collaborator to a repository.

        :param username:
            (required), username of the user
        :type username:
            str or :class:`~github3.users.User`
        :returns:
            True if successful, False otherwise
        :rtype:
        """
        if not username:
            return False
        url = self._build_url(
            "collaborators", str(username), base_url=self._api
        )
        return self._boolean(self._put(url), 201, 404)

[froi]

Hello everybody. 👋🏼

Is there any appetite for a PR that add this functionality?