py38 deprecation warnings

[stas00]

Please kindly fix these for py38:

python3.8/site-packages/wandb/util.py:36: 
DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.9 it will stop working
  from collections import namedtuple, Mapping, Sequence
python3.8/site-packages/wandb/vendor/graphql-core-1.1/graphql/type/directives.py:55: 
DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.9 it will stop working
  assert isinstance(locations, collections.Iterable), 'Must provide locations for directive.'

the first one is just s/collections/collections.abc/, but the second one is an outdated package.

Thank you!

[tyomhak]

Hey @stas00 , thank you for reporting this.
@vanpelt can you please take a look?

[SylvainLan]

Hi !
I'm new to wandb and got this warning as well, even after installed it through github and not pip.
The flagged file was wandb/vendor/watchdog/utils/bricks.py:175, do you want me to run a small PR ? I can take a look at the merged PR from above