2.1.1

This is a gem housekeeping release. There should be no user-facing changes.

🏠 Housekeeping

• Migrate from travis-ci.org to travis-ci.com (#96) @mattbrictson
• Set up automerge using kodiak bot (#91) @mattbrictson
• Create Dependabot config file (#92) @dependabot-preview
• Install and configure rubocop-rake (#100) @mattbrictson
• Upgrade CI to Ruby 2.7.2 (#93) @mattbrictson
• Update rubocop requirement from 0.92.0 to 1.5.2 (#95, #97, #99) @dependabot
• Update rubocop-performance requirement from 1.8.1 to 1.9.1 (#98) @dependabot
• Update rubocop-packaging requirement from 0.5.0 to 0.5.1 (#94) @dependabot