use slug for team name

[mtgto]

It should use team.slug instead of team.name.

GitHub API uses the team's slug as parameter, which is generated by team's name.
ex. https://developer.github.com/v3/teams/#get-a-team-by-name

For instance, Jasper recognize team name as "foo/bar@baz" if team name is "foo/bar@baz".
But github creates slug as "bar-baz".

[h13i32maru]

👍