0.8.0

⚠️ Breaking Changes

• Drop support for Ruby 2.3 (#19) @mattbrictson

🏠 Housekeeping

• Eliminate double Travis CI builds on PRs (#22) @mattbrictson
• Add rubocop-performance gem (#21) @mattbrictson
• Switch to ruby 1.9 hash syntax (#20) @mattbrictson
• Set up release-drafter (#18) @mattbrictson
• Update rubocop dev dependency to 0.71.0 (#17) @dependabot-preview
• Work around rvm ruby-head failures on Travis (#6) @mattbrictson
• Upgrade bundler; add Ruby 2.6 to Travis matrix (#5) @mattbrictson