Log Message:
time/ruby-tzinfo: update to 1.2.5

Version 1.2.5 - 4-Feb-2018
--------------------------

* Support recursively (deep) freezing Country and Timezone instances. #80.
* Allow negative daylight savings time offsets to be derived when reading from
  zoneinfo files. The utc_offset and std_offset are now derived correctly for
  Europe/Dublin in the 2018a and 2018b releases of the Time Zone Database.