Fixes docs link for 'PATCH /repos/:owner/:repo'.
Fixes docs link for 'PATCH /repos/:owner/:repo'.

The link https://developer.github.com/v3/repos/#edit does not exist anymore.
Instead it is now https://developer.github.com/v3/repos/#update-a-repository.

octokit/octokit.rb,octokit/octokit.rb