Fix collections import DeprecationWarning

[BeyondEvil]

Import ABCs from collections is deprecated and will stop working in python 3.8.
https://github.com/python/cpython/blob/master/Lib/collections/__init__.py#L49

Starting with python 3.3 any imported ABCs should come from collections.abc
https://docs.python.org/3/library/collections.abc.html

The warning looks like this:

/lib/python3.7/site-packages/sentry_sdk/utils.py:8: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working
  from collections import Mapping, Sequence

[codecov-io]

Codecov Report

Merging #165 into master will decrease coverage by 0.51%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #165      +/-   ##
==========================================
- Coverage   67.58%   67.06%   -0.52%     
==========================================
  Files          28       28              
  Lines        2770     2772       +2     
  Branches      434      435       +1     
==========================================
- Hits         1872     1859      -13     
- Misses        729      743      +14     
- Partials      169      170       +1

Impacted Files	Coverage Δ
sentry_sdk/utils.py	70.4% <100%> (+0.11%)	⬆️
sentry_sdk/integrations/aws_lambda.py	0% <0%> (-12.72%)	⬇️

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[BeyondEvil]

I fixed the linting error (blacks trailing comma... sigh)

But the other 4 failures (all the same The command "sh scripts/download-semaphore.sh" failed and exited with 1 during .) I'm not sure I have any control over. 🤷‍♂️

[untitaker]

Thanks!