A dependency on ~> 9.0.0 results in only versions 9.0.x being compatible. Under the assumption WordPressKit always respects semantic versioning, that approach limits the versions WordPressAuthenticator can be compatible with. In particular, prevents seamlessly using something like WordPressKit 9.1.0 in a client of both WordPressAuthenticator and WordPressKit.
A dependency on
~> 9.0.0results in only versions9.0.xbeing compatible. Under the assumption WordPressKit always respects semantic versioning, that approach limits the versions WordPressAuthenticator can be compatible with. In particular, prevents seamlessly using something like WordPressKit 9.1.0 in a client of both WordPressAuthenticator and WordPressKit.Case in point, I just created WordPressKit 9.0.3, https://github.com/wordpress-mobile/WordPressKit-iOS/pull/677, in place of 9.1.0 in order to avoid having to ship a new WordPressAuthenticator version in the middle of a release cycle.
CHANGELOG.mdif necessary.