It seems IHostingEnvironment has been replaced by IHostEnvironment (and a few others).
You should be able to change the interface type in your code and everything will work as it used to 🙂
You can find more information about the changes at this link on GitHub
https://github.com/aspnet/AspNetCore/issues/7749
EDIT
There is also an additional interface IWebHostEnvironment that can be used in ASP.NET Core applications. This is available in the Microsoft.AspNetCore.Hosting namespace.