Update isort to 5.6.3

[pyup-bot]

This PR updates isort from 5.6.1 to 5.6.3.

Changelog

5.6.3

- Improved packaging of test files alongside source distribution (see: https://github.com/PyCQA/isort/pull/1555).

5.6.2

- Fixed 1548: On rare occasions an unecessary empty line can be added when an import is marked as skipped.
- Fixed 1542: Bug in VERTICAL_PREFIX_FROM_MODULE_IMPORT wrap mode.
- Fixed 1552: Pylama test dependent on source layout.

Goal Zero: (Tickets related to aspirational goal of achieving 0 regressions for remaining 5.0.0 lifespan):
- Zope added to integration test suite
- Additional testing of CLI (simulate unseekable streams)

Links

• PyPI: https://pypi.org/project/isort
• Changelog: https://pyup.io/changelogs/isort/
• Repo: https://pycqa.github.io/isort/