Fix build

Author: JamesNK

src/Middleware/CORS/src/Microsoft.AspNetCore.Cors.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>CORS middleware and policy for ASP.NET Core to enable cross-origin resource sharing.
@@ -13,6 +13,7 @@ Microsoft.AspNetCore.Cors.EnableCorsAttribute</Description>
 
   <ItemGroup>
     <Reference Include="Microsoft.AspNetCore.Http.Extensions" />
+    <Reference Include="Microsoft.AspNetCore.Routing" />
     <Reference Include="Microsoft.Extensions.Configuration.Abstractions" />
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions" />
     <Reference Include="Microsoft.Extensions.Logging.Abstractions" />