Sync zoneinfo database with tzdata2020b from ftp://ftp.iana.org/tz/releases

Sync zoneinfo database with tzdata2020b from ftp://ftp.iana.org/tz/releases

* Revised predictions for Morocco's changes starting in 2023.

* Canada's Yukon changes to -07 on 2020-11-01, not 2020-03-08.

* Macquarie Island has stayed in sync with Tasmania since 2011.

* Casey, Antarctica is at +08 in winter and +11 in summer.

* Various other fixes and corrections in past timestamps.

For a detailed list of changes, see share/zoneinfo/NEWS.