Update pyowm to 3.1.1

[pyup-bot]

This PR updates pyowm from 3.0.0 to 3.1.1.

Changelog

3.1.1

----------------------------
Bugfixes:
- Minutely rain data on OneCall calls were not read by PyOWM
- Fixed bugs in code recipes

3.1.0

New features:
- Support for OneCall minutely forecast data

Enhancements:
- OneCall calls now support [`units` and `exclude` parameters](https://openweathermap.org/api/one-call-api)
- queries to weather objects now support new visibility distance (miles) and barometric pressure (InHG) units
- now it is possible to obtain weather icons in 2 sizes (2x, 4x)
- all PyOWM timestamps are now timezone-aware
- now PyOWM exposes a list of OWM supported languages (`pyowm.constants.LANGUAGES`)
- added an FAQ page to the documentation

Bugfixes:
- tons on the documentation
- removed dependency version pinning on `PySocks`
- patched wrong subdomains for paid API calls

Links

• PyPI: https://pypi.org/project/pyowm
• Changelog: https://pyup.io/changelogs/pyowm/
• Repo: https://github.com/csparpa/pyowm