Update our 2018 release schedule wrt. new Firefox ESR plans
Next ESR will be Firefox 60. https://wiki.mozilla.org/RapidRelease/Calendar was updated.
- RM shifts
- sponsor deliverables
- anonym who’ll do the work on #15023 (closed)
- intrigeri who’ll review #15023 (closed)
- tails-dev@ and workers for sponsor deliverables
- Redmine target version dates