zsh-syntax-highlighting/release.md

Release procedure (for developers):

• Check open issues and outstanding pull requests
• Confirm make test passes
  • check with multiple zsh versions
• Update changelog.md
• Update ./.version
• git tag -am "Release $(<.version)" zsh-syntax-highlighting-"$(<.version)" && git push --tags
• perl -pi -e 's/$/-dev/' ./.version
• Notify downstreams (OS packages)
  • anitya should autodetect the tag