Capitalization of the 2FA OTP request header

Author: tradej

github/AuthenticatedUser.py

@@ -426,7 +426,7 @@ def create_authorization(self, scopes=github.GithubObject.NotSet, note=github.Gi
         if client_secret is not github.GithubObject.NotSet:
             post_parameters["client_secret"] = client_secret
         if onetime_password is not None:
-            request_header = {'x-github-otp': onetime_password}  # pragma no cover (Should be covered)
+            request_header = {'X-GitHub-OTP': onetime_password}  # pragma no cover (Should be covered)
         else:
             request_header = None
         headers, data = self._requester.requestJsonAndCheck(