update version for `Microsoft.AspNet.Mvc`

[cottsak]

A common problem is updating the tests packages.config from Microsoft.AspNet.Mvc 5.2.2 to Microsoft.AspNet.Mvc 5.2.3. Perhaps we can use a version range https://docs.nuget.org/create/versioning for this package in https://github.com/cottsak/ControllerTests/blob/master/ControllerTests/ControllerTests.nuspec