Fix integration test due to breaking change in latest Octokit.net release

Author: hnrkndrssn

src/ScriptCs.Octokit.Sample/sample.csx

@@ -4,7 +4,7 @@ var userTask = client.User.Get("alfhenrik");
 var user = userTask.Result;
 Console.WriteLine(user.Name);
 
-var repoTask = client.Repository.GetAllBranches("alfhenrik", "octokit.net");
+var repoTask = client.Repository.Branch.GetAll("alfhenrik", "octokit.net");
 var branches = repoTask.Result;
 Console.WriteLine(branches.Count);
 foreach(var branch in branches)