Using the SHA-256 Hash Algorithm (or SHA2) Using ASP.NET Identity 2.2.1

Question

I am working on a project that uses ASP.NET Identity 2.2.1. I have a requirement to use the SHA-2 family hash algorithm to hash passwords. The ASP.NET Identity 2.2.1 hash algorithm is HMACSHA-1 (+ salt, etc.), while version 3 (In Beta) uses HMACSHA-256.

Source: https://github.com/aspnet/Identity/blob/dev/src/Microsoft.AspNet.Identity/PasswordHasher.cs

Can someone help with ideas to implement the SHA-256 hash algorithm using ASP.NET Identity version 2.2.1?