[FIX] Update checker: LooseVersion doesn't handle str parts

[kernc]

Issue

>>> from distutils.version import LooseVersion
>>> LooseVersion('3.4.dev') <= LooseVersion('3.4.1')
--------------------------------------------------------------------------------
TypeError: unorderable types: str() < int()

Description of changes

Use newer package_resources.SetuptoolsVersion which doesn't exhibit this problem.

Includes

• Code changes
• Tests
• Documentation

[kernc]

https://sentry.io/biolab/orange3/issues/293383178/

[codecov-io]

Codecov Report

Merging #2401 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2401      +/-   ##
==========================================
- Coverage   73.88%   73.88%   -0.01%     
==========================================
  Files         322      322              
  Lines       55843    55843              
==========================================
- Hits        41262    41257       -5     
- Misses      14581    14586       +5

[astaric]

Are you sure this one handles everything? Would it be possilble to add some tests?

[astaric]

PS. Could you also add a trailing / to the URL used to check the version (to avoid unnecessary redirects)?