get_last_modified and localization

[NicolasGoeddel]

Owncloud gives my me a date in the form Sat, 20 Feb 2021 06:05:22 GMT but my python code uses the german locale settings de_DE.UTF-8. Because of that I run into a ValueError:

  Module sw.utilities.utilities.owncloud, line 288, in get_last_modified
  Module _strptime, line 565, in _strptime_datetime
  Module _strptime, line 362, in _strptime
ValueError: time data 'Sat, 20 Feb 2021 06:05:22 GMT' does not match format '%a, %d %b %Y %H:%M:%S %Z'

In this case it expects the string Sa (Samstag) instead if Sat (Saturday). This case should be fixed so that the date parsing is independent from the locale settings of the rest of the code. The same happens if the english month is different from the one in any other language.
It would be best if this also works in a multithreaded environment where changing the locale settings temporarily is not a good idea I guess.