Fix #524 - Restrict usage of timezone aware expire dates to Django projects with USE_TZ set to True

[JadielTeofilo]

Fixes #

Description of the Change

Fixes #524. Restrict usage of timezone aware expire dates to Django projects with USE_TZ set to True.

Checklist

• PR only contains one change (considered splitting up PR)
• unit-test added
• documentation updated
• CHANGELOG.md updated (only for user relevant changes)
• author name in AUTHORS

[auvipy]

please check the test failures

[codecov]

Codecov Report

Merging #948 (921cef6) into master (5d53d24) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #948   +/-   ##
=======================================
  Coverage   96.59%   96.59%           
=======================================
  Files          31       31           
  Lines        1704     1704           
=======================================
  Hits         1646     1646           
  Misses         58       58           

Impacted Files	Coverage Δ
oauth2_provider/oauth2_validators.py	93.57% <100.00%> (ø)

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[n2ygk]

Thanks!