Bump Microsoft.NET.Test.Sdk from 17.11.1 to 17.12.0 in /src/Objectivity.AutoFixture.XUnit2.AutoMoq.Tests

Bump Microsoft.NET.Test.Sdk from 17.11.1 to 17.12.0 in /src/Objectivity.AutoFixture.XUnit2.AutoMoq.Tests #623