Fix build error

src/DotNetCore.CAP.Dashboard/LocalRequestsOnlyAuthorizationFilter.cs

 // Copyright (c) .NET Core Community. All rights reserved.
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
+using System.Threading.Tasks;
 using DotNetCore.CAP.Internal;
 
 namespace DotNetCore.CAP.Dashboard
 {
     public class LocalRequestsOnlyAuthorizationFilter : IDashboardAuthorizationFilter
     {
-        public bool Authorize(DashboardContext context)
+        public Task<bool> AuthorizeAsync(DashboardContext context)
         {
             var ipAddress = context.Request.RemoteIpAddress;
             // if unknown, assume not local
             if (string.IsNullOrEmpty(ipAddress))
             {
-                return false;
+                return Task.FromResult(false);
             }
 
             // check if localhost
             if (ipAddress == "127.0.0.1" || ipAddress == "0.0.0.1")
             {
-                return true;
+                return Task.FromResult(true);
             }
 
             // compare with local address
             if (ipAddress == context.Request.LocalIpAddress)
             {
-                return true;
+                return Task.FromResult(true);
             }
 
             // check if private ip
             if (Helper.IsInnerIP(ipAddress))
             {
-                return true;
+                return Task.FromResult(true);
             }
 
-            return false;
+            return Task.FromResult(false);
         }
     }
 }
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