modernize setup.cfg and pyproject.toml

[shimizukawa]

Feature or Bugfix

• Feature

Purpose

• Move setup.py parameters into setup.cfg

Detail

• Since setuptools-30.3.0 (8 Dec 2016), almost all parameters can now be written in setup.cfg.

Relates

• https://setuptools.readthedocs.io/en/latest/userguide/declarative_config.html

[codecov]

Codecov Report

Merging #77 (66dc1fe) into master (16dcd4a) will increase coverage by 1.52%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #77      +/-   ##
==========================================
+ Coverage   45.49%   47.01%   +1.52%     
==========================================
  Files           3        3              
  Lines         244      251       +7     
  Branches       62       62              
==========================================
+ Hits          111      118       +7     
  Misses        123      123              
  Partials       10       10              

Impacted Files	Coverage Δ
django_redshift_backend/__init__.py	100.00% <100.00%> (ø)

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[shimizukawa]

Uploaded information on test pypi looks fine.
https://test.pypi.org/project/django-redshift-backend/2.0.2.dev8/

[shimizukawa]

PyPI does not allow local-version part +ga4d8bf9

> twine upload -r testpypi dist\django-redshift-backend-2.0.2.dev8+ga4d8bf9.tar.gz
Uploading distributions to https://test.pypi.org/legacy/
Uploading django-redshift-backend-2.0.2.dev8+ga4d8bf9.tar.gz
...
HTTPError: 400 Bad Request from https://test.pypi.org/legacy/
'2.0.2.dev8+ga4d8bf9' is an invalid value for Version. Error: Can't use PEP 440 local versions. See https://packaging.python.org/specifications/core-metadata for more information.