Updated SetOptions logic to allow calling on client without credentials

CryptoExchange.Net/Objects/Options/UpdateOptions.cs

@@ -6,19 +6,27 @@ namespace CryptoExchange.Net.Objects.Options
     /// <summary>
     /// Options to update
     /// </summary>
-    public class UpdateOptions<TApiCredentials> where TApiCredentials : ApiCredentials
+    public class UpdateOptions
     {
         /// <summary>
         /// Proxy setting. Note that if this is not provided any previously set proxy will be reset
         /// </summary>
         public ApiProxy? Proxy { get; set; }
         /// <summary>
-        /// Api credentials
-        /// </summary>
-        public TApiCredentials? ApiCredentials { get; set; }
-        /// <summary>
         /// Request timeout
         /// </summary>
         public TimeSpan? RequestTimeout { get; set; }
     }
+
+    /// <summary>
+    /// Options to update
+    /// </summary>
+    public class UpdateOptions<TApiCredentials>: UpdateOptions
+        where TApiCredentials : ApiCredentials
+    {
+        /// <summary>
+        /// Api credentials
+        /// </summary>
+        public TApiCredentials? ApiCredentials { get; set; }
+    }
 }