Update Swashbuckle.AspNetCore to 4.0.0

Author: RehanSaeed

Source/Boxed.AspNetCore.Swagger/Boxed.AspNetCore.Swagger.csproj

@@ -9,7 +9,7 @@
   </PropertyGroup>
 
   <PropertyGroup Label="Package">
-    <VersionPrefix>3.0.1</VersionPrefix>
+    <VersionPrefix>4.0.0</VersionPrefix>
     <Authors>Muhammad Rehan Saeed (RehanSaeed.com)</Authors>
     <Product>ASP.NET Core Swagger Framework Boxed</Product>
     <Description>Provides ASP.NET Core middleware, MVC filters, extension methods and helper code for an ASP.NET Core project implementing Swagger (OpenAPI).</Description>
@@ -46,7 +46,7 @@
   <ItemGroup Label="Package References">
     <PackageReference Condition="'$(OS)' == 'Windows_NT'" Include="Microsoft.SourceLink.GitHub" PrivateAssets="All" Version="1.0.0-beta-63127-02" />
     <PackageReference Include="StyleCop.Analyzers" PrivateAssets="All" Version="1.1.0-beta009" />
-    <PackageReference Include="Swashbuckle.AspNetCore" Version="3.0.0" />
+    <PackageReference Include="Swashbuckle.AspNetCore" Version="4.0.0" />
   </ItemGroup>
 
 </Project>

Source/Boxed.AspNetCore.Swagger/SwaggerGenOptionsExtensions.cs

@@ -3,6 +3,7 @@ namespace Boxed.AspNetCore.Swagger
     using System;
     using System.IO;
     using System.Reflection;
+    using Microsoft.Extensions.DependencyInjection;
     using Swashbuckle.AspNetCore.SwaggerGen;
 
     /// <summary>