Upgrade to .NET Core 3.1

[Piedone]

The good news is that this is already done in this fork: https://github.com/czmirek/AspNet.Mvc.TypedRouting

[howcheng]

Can you create a pull request for this? I'm trying to use this package in a .NET 6 app and I think the dependency on Microsoft.AspNetCore.Mvc is preventing the build from succeeding (error: "namespace" is a reserved word and cannot be used in implicit expressions. An explicit expression ("@()") must be used.)

I'll probably take your fork and make a local package on our Azure DevOps feed for the time being.

[Piedone]

Note that the fork is not mine, I just noticed somebody else's. I haven't used this project since then and thus are not active in it, but yeah, now, two years later, it should really be .NET 6 instead.