fix: remove redudant rule

Author: bielu

src/ByteBard.AsyncAPI/Validation/Rules/AsyncApiServerRules.cs

@@ -6,7 +6,6 @@
     [AsyncApiRule]
     public static class AsyncApiServerRules
     {
-        [AsyncApiVersionRule(AsyncApiVersion.AsyncApi3_0)]
         public static ValidationRule<AsyncApiServer> ServerRequiredFields =>
             new ValidationRule<AsyncApiServer>(
                 (context, server) =>
@@ -29,32 +28,6 @@ public static class AsyncApiServerRules
                             string.Format(Resource.Validation_FieldRequired, "protocol", "server"));
                     }
 
-                    context.Exit();
-                });
-
-        [AsyncApiVersionRule(AsyncApiVersion.AsyncApi2_0)]
-        public static ValidationRule<AsyncApiServer> V2ServerRequiredFields =>
-            new ValidationRule<AsyncApiServer>(
-                (context, server) =>
-                {
-                    context.Enter("url");
-                    if (server.Host == null)
-                    {
-                        context.CreateError(
-                            nameof(V2ServerRequiredFields),
-                            string.Format(Resource.Validation_FieldRequired, "url", "server"));
-                    }
- 
-                    context.Exit();
-
-                    context.Enter("protocol");
-                    if (server.Protocol == null)
-                    {
-                        context.CreateError(
-                            nameof(V2ServerRequiredFields),
-                            string.Format(Resource.Validation_FieldRequired, "protocol", "server"));
-                    }
-
                     context.Exit();
                 });
     }