Bump botocore dependency specification

[jakob-keller]

Description of Change

This PR intends to improve general compatibility of aiobotocore within the Python ecosystem by bumping the dependency specification of botocore, as well as boto3 and awscli.

Assumptions

Upstream diff contains several changes that require minor adjustments to the aiobotocore codebase.

Checklist for All Submissions

• I have added change info to CHANGES.rst
• If this is resolving an issue (needed so future developers can determine if change is still necessary and under what conditions) (can be provided via link to issue with these details):
  • Detailed description of issue
  • Alternative methods considered (if any)
  • How issue is being resolved
  • How issue can be reproduced
• If this is providing a new feature (can be provided via link to issue with these details):
  • Detailed description of new feature
  • Why needed
  • Alternatives methods considered (if any)

Checklist when updating botocore and/or aiohttp versions

• I have read and followed CONTRIBUTING.rst
• I have updated test_patches.py where/if appropriate (also check if no changes necessary)
• I have ensured that the awscli/boto3 versions match the updated botocore version

[codecov]

Codecov Report

Attention: Patch coverage is 57.14286% with 3 lines in your changes missing coverage. Please review.

Project coverage is 89.78%. Comparing base (3eabc88) to head (2498e62).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
aiobotocore/httpchecksum.py	57.14%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1292      +/-   ##
==========================================
- Coverage   89.88%   89.78%   -0.11%     
==========================================
  Files          67       67              
  Lines        6083     6087       +4     
==========================================
- Hits         5468     5465       -3     
- Misses        615      622       +7     

Flag	Coverage Δ
unittests	89.78% <57.14%> (-0.11%)	⬇️

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[jakob-keller]

Test coverage is slightly lower, but the non-covered lines are also not tested in upstream. I'd say this is fine.

[jakob-keller]

@thehesiod: Thanks for the review and approval! Is there a way for you to unblock the PR, i.e. force it into the merge queue despite the coverage fail? I can't do that AFAIK.