2.2.1

This is a gem housekeeping release. No user-facing changes.

🏠 Housekeeping

• Update rubocop-minitest requirement from 0.14.0 to 0.15.2 (#135, #136, #139) @dependabot
• Update rubocop requirement from 1.18.3 to 1.22.1 (#131, #133, #137, #138) @dependabot
• Update rubocop-performance requirement from 1.11.4 to 1.11.5 (#134) @dependabot
• Remove unnecessary Gem::Requirement class (#132) @mattbrictson