Edit issue should work with IssueNumber instead of `Id Issue`

[vrom911]

As per the specifications, the endpoint should contain the issue number, not the issue ID.

Currently, editIssueR has the following type:

editIssueR :: Name Owner -> Name Repo -> Id Issue -> EditIssue -> Request 'RW Issue

I propose to change it to:

editIssueR :: Name Owner -> Name Repo -> IssueNumber -> EditIssue -> Request 'RW Issue

[phadej]

Thanks for catching this. PR would be nice.