[release] 1.1.0 🎉

[eonu]

Major changes

• Change bundler requirement to >= 1.17 in arx.gemspec. (#53)
• Remove Arx.find alias of Arx.search. (#57)
• Add Query#group for subquery grouping support. (#59)

Minor changes

• Add contributing guidelines (CONTRIBUTING.md). (#48)
• Add issue templates to ./github/ISSUE_TEMPLATE for (#49, #54, #55):
  • Error or warning
    For reporting an error or warning generated by Arx.
  • Unexpected or incorrect functionality
    For reporting something that doesn't seem to be working correctly or is unexpected.
  • Improvement to an existing feature
    For suggesting an improvement to a feature already offered by Arx.
  • Suggesting a new feature
    For proposing a new feature to Arx that would be beneficial.
• Add a pull request template at ./github/PULL_REQUEST_TEMPLATE.md. (#49)
• Remove issue templates from CONTRIBUTING.md. (#49)
• Remove LICENSE from YARD documentation (remove from .yardopts). (#50)
• Add RVM ruby version 2.6 to .travis.yml. (#53)
• Add contributor code-of-conduct (CODE_OF_CONDUCT.md). (#56)
• Thank Scholastica in README.md. (#58)
• Add bin/console for gem debugging. (#60)
• Modify gem:debug rake task to run bin/console. (#60)