Because the prior 5.0.2 release removed the State type parameter from Location, this was technically a breaking change. To correct for this, I'm bumping this as a minor release. It won't affect runtime code, but it may affect your development experience and tests if you were using that parameter.
The State type export is also restored, so you shouldn't have issues with installing React Router v6.
Oh, by the way, did you hear we released React Router v6?
Full Changelog: v5.0.3...v5.1.0