Test suite broken under python 3.10+ (nose not maintained)

[mpaulon]

Running the s3-tests with S3TEST_CONF=conf ./virtualenv/bin/nosetests return the following traceback:

  File "/home/michael/git/s3flask/s3-tests/virtualenv/lib/python3.10/site-packages/nose/suite.py", line 106, in _set_tests
    if isinstance(tests, collections.Callable) and not is_suite:
AttributeError: module 'collections' has no attribute 'Callable'

Callable has been moved under collections.abc as of python 3.10.
There is the following issue opened on the nose github, but the nose test framework has been unmaintained for several years and it looks like it wont be updated for python 3.10+.

[cbodley]

thanks @mpaulon. we had to use older python as a workaround for a long time, but this was finally resolved in #482