MFC: contrib/tzdata: import tzdata 2020e
Changes: https://github.com/eggert/tz/blob/2020e/NEWS
(cherry picked from commit dc505d53dcc15636aea9df8c03298f8c32147fa9)
(cherry picked from commit 1a8f8af03320165b33526d44de4f12360aa5440a)
Approved by: so