Bump pylint from 2.5.3 to 2.6.0 in /cvat/requirements (#2063)

Bumps [pylint](https://github.com/PyCQA/pylint) from 2.5.3 to 2.6.0.
- [Release notes](https://github.com/PyCQA/pylint/releases)
- [Changelog](https://github.com/PyCQA/pylint/blob/master/ChangeLog)
- [Commits](https://github.com/PyCQA/pylint/compare/pylint-2.5.3...pylint-2.6.0)

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Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

cvat/requirements/development.txt

@@ -3,7 +3,7 @@ astroid==2.4.2
 isort==4.3.21
 lazy-object-proxy==1.5.1
 mccabe==0.6.1
-pylint==2.5.3
+pylint==2.6.0
 pylint-django==2.3.0
 pylint-plugin-utils==0.6
 rope==0.17.0