Updated readme with v5/canary changes
Updated readme with v5/canary changes

refs https://github.com/TryGhost/Toolbox/issues/240
refs https://github.com/TryGhost/gscan/pull/251/commits/cf265d88a2b9da5febbb211992958d2c303500ad

- Makes sure documentation is up to date

TryGhost/gscan