CRM-6614: Master instance couldn't be rebuilt (#4099)
CRM-6614: Master instance couldn't be rebuilt (#4099)

- added section authors in composer.json
- updated Upgrade-2.0 md. Added information about the command "oro:platform:upgrade20"
orocrm/OroCalendarBundle,orocrm/OroCalendarBundle,orocrm/OroCalendarBundle