BREAKING CHANGE (behavior): Modify caching to only attempt to update the response cache if a 2xx response code is received from GitHub (#2877)

Only update response cache for successful api responses

Co-authored-by: Nick Floyd <139819+nickfloyd@users.noreply.github.com>

Octokit/Helpers/HttpExtensions.cs

@@ -0,0 +1,26 @@
+using System.Threading;
+using System.Threading.Tasks;
+using Octokit.Internal;
+
+namespace Octokit
+{
+    public static class HttpExtensions
+    {
+        public static Task<IResponse> Send(this IHttpClient httpClient, IRequest request)
+        {
+            Ensure.ArgumentNotNull(httpClient, nameof(httpClient));
+            Ensure.ArgumentNotNull(request, nameof(request));
+
+            return httpClient.Send(request, CancellationToken.None);
+        }
+
+        /// <summary>
+        /// Gets a value that indicates whether the HTTP response was successful.
+        /// </summary>
+        public static bool IsSuccessStatusCode(this IResponse response)
+        {
+            Ensure.ArgumentNotNull(response, nameof(response));
+            return (int) response.StatusCode >= 200 && (int) response.StatusCode <= 299;
+        }
+    }
+}