Can't search repos with underscore in repo name

[dsplaisted]

The following test fails:

    [IntegrationTest]
    public async Task SearchForFileNameInCodeWithoutTermWithUnderscore()
    {
        var request = new SearchCodeRequest()
        {
            FileName = "readme.md",
            Repos = new RepositoryCollection { "Cultural-Rogue/_51Wp.XinFengSDK.Demo" }
        };

        var repos = await _gitHubClient.Search.SearchCode(request);
    }

It fails with the following exception:

Octokit.RepositoryFormatException : The list of repositories must be formatted as 'owner/name' - these values don't match this rule: Cultural-Rogue/_51Wp.XinFengSDK.Demo
at Octokit.SearchCodeRequest.MergedQualifiers() in C:\git\octokit.net\Octokit\Models\Request\SearchCodeRequest.cs:line 204
   at Octokit.BaseSearchRequest.get_TermAndQualifiers() in C:\git\octokit.net\Octokit\Models\Request\BaseSearchRequest.cs:line 87
   at Octokit.BaseSearchRequest.get_Parameters() in C:\git\octokit.net\Octokit\Models\Request\BaseSearchRequest.cs:line 106
   at Octokit.SearchClient.SearchCode(SearchCodeRequest search) in C:\git\octokit.net\Octokit\Clients\SearchClient.cs:line 67
   at SearchClientTests.<SearchForFileNameInCodeWithoutTermWithUnderscore>d__8.MoveNext() in C:\git\octokit.net\Octokit.Tests.Integration\Clients\SearchClientTests.cs:line 99
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

The culprit seems to be this Regex. With a quick search I couldn't find documentation on what the allowed formats for GitHub usernames and repo names are, so I don't know if adding an underscore to the Regex is all that's needed or if there are other possibilities. Perhaps there's no need to do client-side validation of this at all.

[shiftkey]

@dsplaisted 👍 to relaxing the regex to include _- I did a quick test of other special characters and the only one I could find permitted is a -