template finder should search both master and main as the default branch

[Guslington]

https://github.com/theonestack/cfhighlander/blob/9eb7fb4c3acad4ba7101a4bad3183ed522ed2b2f/lib/cfhighlander.factory.templatefinder.rb#L40

As the default branch is now main cfhighlander needs to default to both master and main to handle this change.