use different timezones to run CI tests

[gutsytechster]

The test fails when it runs at midnight or, in general, when a time difference causes changes in dates for UTC and non-UTC time zones.

Some tests expect the local timezone to be picked resulting in a different expectation than the actual result. The result of the search_dates method picks UTC when nothing is provided in the absence of date & time.

Additionally, I reckon the issue was introduced in #1111, where datetime.datetime.utcnow().month was replaced with datetime.datetime.today().month.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.14%. Comparing base (02bd2e5) to head (30c4bd3).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1259   +/-   ##
=======================================
  Coverage   98.14%   98.14%           
=======================================
  Files         234      234           
  Lines        2748     2748           
=======================================
  Hits         2697     2697           
  Misses         51       51           

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[gutsytechster]

@Gallaecio yeah. The only difference between the two is that one observes DST while the other doesn't. So I kept both of them.