v2.1.0

This release adds Ruby 3.0+ support.

Due to kwarg changes in ruby 3, we have bumped the minimum required version of Rack to 2.2.3, which is where ruby3 support was added.

Releasing as a minor as dependency resolution should fail at install if an application is locked to a rack below new minimum.

Full Changelog: v2.0.4...v2.1.0