contrib/tzdata: import tzdata 2022a

Merge commit '971fa603f2bdf16273135a00ff16c5585520c53f'

Changes: https://github.com/eggert/tz/blob/2022a/NEWS

With this merge, we return to our previous long-standing practice of
distributing the IANA Time Zone Database unmodified.

Releases of tzdb since 2021b have merged some time zones where clocks
have agreed since 1970. The overwhelming majority of users will not be
affected by this change. A port of the newly created global-tz fork of
the IANA Time Zone database (misc/global-tz) is available for users who
need more granular pre-1970 time zone history.

Approved by: re (gjb)

(cherry picked from commit 8ea5af2b77f2b43c250cacb257f42c0a54d644c4)
(cherry picked from commit 5dbd160076c09b0a3c7b175b506a57bd8b71f22a)