The internal representation of timezones in the reflog for the
reftable format has been fixed to match the specification, which
dictates an offset in minutes rather than the parsed "+HHMM" integer
representation.
* ps/reftable-reflog-timezone:
refs/reftable: fix on-disk representation of reflog timezones
t/helper: fix segfault in "dump-reftable -t"
date: add helpers to convert between "+HHMM" timezones and minutes