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 95.85253% with 9 lines in your changes missing coverage. Please review.

Project coverage is 89.04%. Comparing base (4a096bd) to head (a540cd5).

Files with missing lines	Patch %	Lines
tests/boto_tests/unit/test_httpchecksum.py	97.14%	6 Missing ⚠️
aiobotocore/httpchecksum.py	57.14%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1292      +/-   ##
==========================================
+ Coverage   87.90%   89.04%   +1.13%     
==========================================
  Files          68       68              
  Lines        5987     6199     +212     
==========================================
+ Hits         5263     5520     +257     
+ Misses        724      679      -45     

Flag	Coverage Δ
unittests	89.04% <95.85%> (+1.13%)	⬆️

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