When checking out trio from the v0.22.0 tag, https://github.com/python-trio/trio/blob/v0.22.0/trio/_version.py incorrectly states the version as:

__version__ = "0.21.0+dev"

Noticed this because we use GitHub archives for packaging on Gentoo, and trio ended up being installed as 0.21.0+dev, therefore breaking version constraints in other packages.