replace DRF @list_route and @detail_route with @action

[n2ygk]

Fixes #657

Description of the Change

DRF 3.10 milestone has dropped the @list_route and @detail_route decorators and replaced them with @action(detail=False) or @action(detail=True) which was added in DRF 3.8.

This fix handles both DRF<=3.7 and >=3.8 cases.

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

[n2ygk]

@sliverc any idea why the codecov statuses appear to be stuck?

[codecov]

Codecov Report

Merging #659 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #659      +/-   ##
==========================================
- Coverage   96.15%   96.14%   -0.02%     
==========================================
  Files          57       56       -1     
  Lines        2889     2876      -13     
==========================================
- Hits         2778     2765      -13     
  Misses        111      111

Impacted Files	Coverage Δ
example/api/resources/identity.py	100% <100%> (ø)	⬆️
example/tests/integration/test_polymorphism.py	100% <0%> (ø)	⬆️
example/models.py	100% <0%> (ø)	⬆️
example/migrations/0007_artproject_description.py

---

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[codecov]

Codecov Report

Merging #659 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #659      +/-   ##
==========================================
- Coverage   96.15%   96.14%   -0.02%     
==========================================
  Files          57       56       -1     
  Lines        2889     2876      -13     
==========================================
- Hits         2778     2765      -13     
  Misses        111      111

Impacted Files	Coverage Δ
example/api/resources/identity.py	100% <100%> (ø)	⬆️
example/tests/integration/test_polymorphism.py	100% <0%> (ø)	⬆️
example/models.py	100% <0%> (ø)	⬆️
example/migrations/0007_artproject_description.py

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7abd764...08cb73f. Read the comment docs.

[sliverc]

I prefer we start cleaning up what DRF versions DJA supports then working around this issue.

See suggestion in #662 how to go about this.

[sliverc]

Closing this PR in favor of #664