Added missing MSBuild integration for coverlet.

Author: tillig

test/Autofac.Extras.AggregateService.Test/Autofac.Extras.AggregateService.Test.csproj

@@ -24,7 +24,8 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="coverlet.collector" Version="1.2.0" />
+    <PackageReference Include="coverlet.collector" Version="1.3.0" />
+    <PackageReference Include="coverlet.msbuild" Version="2.9.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.7.1" />
     <PackageReference Include="Moq" Version="4.14.6" />
     <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.113">