Make mungegithub follow github changes

This makes mungegithub follow github changes to avoid errors::

 mungegithub/github/github.go:723:29: cannot use
   prot.RequiredPullRequestReviews (type *github.PullRequestReviewsEnforcement)
   as type *github.PullRequestReviewsEnforcementRequest in field value
 mungegithub/github/github.go:1360:10: cannot use
   listOpts (type *github.ListOptions)
   as type *github.ListCollaboratorsOptions in argument to
   config.client.Repositories.ListCollaborators

mungegithub/github/github.go

@@ -720,7 +720,7 @@ func (config *Config) SetBranchProtection(name string, contexts []string) error
 			Strict:   false,
 			Contexts: contexts,
 		},
-		RequiredPullRequestReviews: prot.RequiredPullRequestReviews,
+		RequiredPullRequestReviews: *github.PullRequestReviewsEnforcementRequest,
 		Restrictions:               unchangedRestrictionRequest(prot.Restrictions),
 		EnforceAdmins:              false,
 	}