Updating BreakingChanges.txt for 1.2 release.
Updating BreakingChanges.txt for 1.2 release.

jbialobr/NSubstitute,iamkoch/NSubstitute,jannickj/NSubstitute,mrinaldi/NSubstitute,huoxudong125/NSubstitute,jbialobr/NSubstitute,jbialobr/NSubstitute,dnm240/NSubstitute,jannickj/NSubstitute,paulcbetts/NSubstitute,huoxudong125/NSubstitute,huoxudong125/NSubstitute,mrinaldi/NSubstitute,jannickj/NSubstitute,dnm240/NSubstitute,iamkoch/NSubstitute,huoxudong125/NSubstitute,iamkoch/NSubstitute,jannickj/NSubstitute,mrinaldi/NSubstitute,iamkoch/NSubstitute,paulcbetts/NSubstitute,paulcbetts/NSubstitute,iamkoch/NSubstitute,jbialobr/NSubstitute,jbialobr/NSubstitute,dnm240/NSubstitute,dnm240/NSubstitute,jannickj/NSubstitute,dnm240/NSubstitute,huoxudong125/NSubstitute,mrinaldi/NSubstitute,mrinaldi/NSubstitute,paulcbetts/NSubstitute