Update the Twitch provider to use the new API

Author: kinosang

src/AspNet.Security.OAuth.Twitch/TwitchAuthenticationDefaults.cs

@@ -36,16 +36,16 @@ public static class TwitchAuthenticationDefaults
         /// <summary>
         /// Default value for <see cref="OAuthOptions.AuthorizationEndpoint"/>.
         /// </summary>
-        public const string AuthorizationEndPoint = "https://api.twitch.tv/kraken/oauth2/authorize";
+        public const string AuthorizationEndPoint = "https://id.twitch.tv/oauth2/authorize";
 
         /// <summary>
         /// Default value for <see cref="OAuthOptions.TokenEndpoint"/>.
         /// </summary>
-        public const string TokenEndpoint = "https://api.twitch.tv/kraken/oauth2/token";
+        public const string TokenEndpoint = "https://id.twitch.tv/oauth2/token";
 
         /// <summary>
         /// Default value for <see cref="OAuthOptions.UserInformationEndpoint"/>.
         /// </summary>
-        public const string UserInformationEndpoint = "https://api.twitch.tv/kraken/user/";
+        public const string UserInformationEndpoint = "https://api.twitch.tv/helix/user/";
     }
 }

src/AspNet.Security.OAuth.Twitch/TwitchAuthenticationHandler.cs

@@ -30,7 +30,7 @@ protected override async Task<AuthenticationTicket> CreateTicketAsync([NotNull]
         {
             var request = new HttpRequestMessage(HttpMethod.Get, Options.UserInformationEndpoint);
             request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
-            request.Headers.Authorization = new AuthenticationHeaderValue("OAuth", tokens.AccessToken);
+            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", tokens.AccessToken);
 
             var response = await Backchannel.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, Context.RequestAborted);
             if (!response.IsSuccessStatusCode)