Feature Request - Provide a 'diff' mode for buildozer

[juanzolotoochin]

It would be very useful if buildozer provided a --mode=diff flag to generate a diff instead of actually doing the changes. This is similar to many other tools that do automatic code manipulation.

In some contexts, like CI, ideally you just want to check if some condition passes without touching files, otherwise then you have to worry about other checks that may be running in parallel and also cleaning up and reverting the changes after the buildozer command has changed the files.