Render meta fields of included resource

[mast22]

Description of the Change

When adding serializer as a field the meta fields are not rendered, This change provides the rendering capability, test and some fixes of related tests.

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

[codecov]

Codecov Report

Merging #883 (95bd302) into master (952e26b) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #883   +/-   ##
=======================================
  Coverage   97.80%   97.80%           
=======================================
  Files          60       60           
  Lines        3321     3325    +4     
=======================================
+ Hits         3248     3252    +4     
  Misses         73       73           

Impacted Files	Coverage Δ
example/tests/test_format_keys.py	100.00% <ø> (ø)
example/tests/test_serializers.py	100.00% <ø> (ø)
example/tests/integration/test_includes.py	100.00% <100.00%> (ø)
example/tests/unit/test_renderer_class_methods.py	100.00% <100.00%> (ø)
rest_framework_json_api/renderers.py	90.09% <100.00%> (-0.10%)	⬇️

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[sliverc]

Thanks a lot for this PR. This brings certainly more consistency to DJA.

I have added some inline comments. Please also add a changelog entry. Thanks.

[sliverc]

Thanks for your contributions. As mentioned above I adjusted your PR a bit but all the rest looked good and ready for merging.

[mast22]

Thanks, and sorry I could not complete it myself. Glad i could help