Bump isort from 5.1.1 to 5.1.4 (pydantic#1742)

Bumps [isort](https://github.com/timothycrosley/isort) from 5.1.1 to 5.1.4.
- [Release notes](https://github.com/timothycrosley/isort/releases)
- [Changelog](https://github.com/timothycrosley/isort/blob/develop/CHANGELOG.md)
- [Commits](PyCQA/isort@5.1.1...5.1.4)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

tests/requirements.txt

@@ -2,7 +2,7 @@ black==19.10b0
 coverage==5.2
 flake8==3.8.3
 flake8-quotes==3.2.0
-isort==5.1.1
+isort==5.1.4
 mypy==0.782
 pycodestyle==2.6.0
 pyflakes==2.2.0