2.2.1

• cask version MAJOR_MINOR_PATCH_REGEX: allow any word character instead of only digits (@vitorgalvao)
• Fix bump-formula-pr on a file with no tap (@fredemmott)
• linkage_checker: whitelist libthread_db.so.1 (@iMichka)
• build: bump listen from 3.2.0 to 3.2.1 in /docs (@Homebrew)
• Fix bug with printing pinned dependencies. (@boblail)
• FormulaInstaller: rescue already attempted install (@scpeters)
• build: bump nokogiri from 1.10.5 to 1.10.7 in /Library/Homebrew (@Homebrew)
• build: bump mustache from 1.1.0 to 1.1.1 in /Library/Homebrew (@Homebrew)
• build: bump github-pages from 202 to 203 in /docs (@Homebrew)
• .github/workflows/tests: run config, doctor. (@MikeMcQuaid)
• extract: semver aware (@figroc)
• Rename Formula#installed? to Formula#latest_version_installed? (@MikeMcQuaid)
• Update formatting of status messages (@EricFromCanada)
• Fixed "Project Leader" link (@tonyravioli)
• os/mac/xcode: add additional CLT download link. (@MikeMcQuaid)
• build: bump zeitwerk from 2.2.1 to 2.2.2 in /Library/Homebrew (@Homebrew)
• README: Remove Patreon badge for consistency amongst donation methods (@issyl0)
• Fix brew cask style. (@MikeMcQuaid)
• Issues: add section for brew config & doctor output (@EricFromCanada)
• workflows/apidoc: try to rebase before pushing. (@MikeMcQuaid)
• build: bump rubocop from 0.76.0 to 0.77.0 in /Library/Homebrew (@Homebrew)
• Update document about Alternative Installation (@raimon49)
• Remove STANDARD_COMPILERS & references to it (@gfguthrie)
• build: bump faraday from 0.17.0 to 0.17.1 in /docs (@Homebrew)
• workflows/tests: tweak behaviour by OS. (@MikeMcQuaid)
• build: bump rubocop-rspec from 1.36.0 to 1.37.0 in /Library/Homebrew (@Homebrew)
• deps: use runtime_dependencies more readily. (@MikeMcQuaid)
• GitHub Actions: get username if we don't have it (@maxim-belkin)