Add verbose logging option to generate_appcast

[latenitefilms]

I'm currently trying to get Sparkle to play nicely in a GitHub Actions workflow.

I just ran into a case where generate_appcast seemed to stall for an hour before I aborted.

I'm ASSUMING it's because there was a popup (or similar) related to Keychain Access.

I can hopefully workaround this by --ed-key-file instead, as per the documentation, however, it would be super handy if generate_appcast could be made to output verbose logging for CI purposes.

[latenitefilms]

Turns out this already exists!

Sparkle/generate_appcast/main.swift

Line 166 in d04faab

var verbose: Bool = false

[zorgiepoo]

Yeah but it's a private option and may not be all that encompassing / formalized. Formalizing it and making it apply for all of generate_appcast's logic might be a reasonable request.