contrib/tzdata: import tzdata 2022a
Merge commit '971fa603f2bdf16273135a00ff16c5585520c53f'
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)