Update isort requirement in /requirements

Updates the requirements on [isort](https://github.com/pycqa/isort) to permit the latest version.
- [Release notes](https://github.com/pycqa/isort/releases)
- [Changelog](https://github.com/PyCQA/isort/blob/main/CHANGELOG.md)
- [Commits](PyCQA/isort@5.7.0...5.13.2)

---
updated-dependencies:
- dependency-name: isort
  dependency-type: direct:development
...

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

requirements/development.txt

@@ -6,5 +6,5 @@ flake8>=3.8,<6.2
 flake8-builtins>=1.5,<2.3
 flake8-isort>=4.0,<6.2
 flake8-qgis>=1,<1.1
-isort>=5.7,<5.13
+isort>=5.7,<5.14
 pre-commit>=2.13,<3.6