🎨 Fix method override warning by adding new keyword to intentional …

…override

Blockmason.Link.Tests/MockHttpClient.cs

@@ -6,7 +6,7 @@ public class MockHttpClient : HttpClient {
     public MockHttpClient() : base() {
     }
 
-    public Task<HttpResponseMessage> SendAsync(HttpRequestMessage request) {
+    public new Task<HttpResponseMessage> SendAsync(HttpRequestMessage request) {
       return new HttpResponseMessage();
     }
   }