Change SyncReport according to the deprecation TODOs

[mlech-reef]

Check TODOs in sync/report.py for details

[mpnowacki-reef]

I don't think this is a part of the public API, so such breaking changes can be done aside from apiver release

[mlech-reef]

SyncReport is part of the public API

[mpnowacki-reef]

You’re right