Add documentation about GitHub draft releases and pre-releases

[jparismorgan]

Hi there, it would be great if we could add documentation about how this handles draft releases and pre-releases on GitHub, i.e. will users automatically download and use those? I believe for draft releases the answer is no because those are private. But I am not sure for pre-releases what the behavior will be.

An extra step would be to also note whether Set as the latest release has any effect, i.e. is that respected here? Or does update-electron-app just pick the highest number release?

Thank you!

[jgresham]

+1