Update tzlocal to 4.2

[pyup-bot]

This PR updates tzlocal from 1.5.1 to 4.2.

Changelog

4.2

----------------

- Nothing changed yet.

4.1

----------------

- No changes from 4.1b1.

4.1b1

------------------

- It turns out a lot of Linux distributions make the links between zoneinfo
aliases backwards, so instead of linking GB to Europe/London it actually
links the other way. When /etc/localtime then links to Europe/London, and you
also have a config file saying Europe/London, the code that checks if
/etc/localtime is a symlink ends up at GB instead of Europe/London and
we get an error, as it thinks GB and Europe/London are different zones.

So now we check the symlink of all timezones in the uniqueness test. We still
return the name in the config file, though, so you would only get GB or Zulu
returned as the time zone instead of Europe/London or UTC if your only
configuration is the /etc/localtime symlink, as that's checked last, and
tzlocal will return the first configuration found.

- The above change also means that GMT and UTC are no longer seen as synonyms,
as zoneinfo does not see them as synonyms. This might be controversial,
but you just have to live with it. Pick one and stay with it. ;-)

4.0.2

------------------

- Improved the error message when you had a conflict including a
/etc/localtime symlink.

4.0.1

------------------

- A long time bug in Ubuntu docker images seem to not get fixed,
so I added a workaround.

4.0.1b1

--------------------

- Handle UCT and Zulu as synonyms for UTC, while treating GMT and
UTC as different.

4.0

----------------

- No changes.

4.0b5

------------------

- Fixed a bug in the Windows DST support.

4.0b4

------------------

- Added support for turning off DST in Windows. That only works in
whole hour timezones, and honestly, if you need to turn off DST,
you should just use UTC as a timezone.

4.0b3

------------------

- Returning pytz_deprecation_shim zones to lower the surprise for pytz users.

- The Windows OS environment variable 'TZ' will allow an override for
setting the timezone. The override timezone will be asserted for
timezone validity bit not compared against the systems timezone offset.
This allows for overriding the timezone when running tests.

- Dropped support for Windows 2000, XP and Vista, supports Windows 7, 8 and 10.

4.0b2

------------------

- Big refactor; Implemented get_localzone_name() functions.

- Adding a Windows OS environment variable 'TZ' will allow an override for
setting the timezone (also see 4.0b3).

4.0b1

------------------

- Now finds and compares all the configs (under Unix-like systems) and
tells you what files it found and how they conflict. This should make
it a lot easier to figure out what goes wrong.

3.0

----------------

- Modernized the packaging, moving to setup.cfg etc.

- Handles if the text config files incorrectly is a TZ file. (revanSZ)

3.0b1

------------------

- Dropped Python 2 support
- Switched timezone provider from pytz to zoneinfo (PEP 615)

2.1

----------------

- No changes.

2.1b1

------------------

- The is_dst flag is wrong for Europe/Dublin on some Unix releases.
I changed to another way of determining if DST is in effect or not.

- Added support for Python 3.7 and 3.8. Dropped 3.5 although it still works.

2.0.0

------------------

- No differences since 2.0.0b3

Links

• PyPI: https://pypi.org/project/tzlocal
• Changelog: https://pyup.io/changelogs/tzlocal/