Bump billiard from 3.6.1.0 to 3.6.2.0 in /requirements (#5950)
Bump billiard from 3.6.1.0 to 3.6.2.0 in /requirements (#5950)

Bumps [billiard](https://github.com/celery/billiard) from 3.6.1.0 to 3.6.2.0.
- [Release notes](https://github.com/celery/billiard/releases)
- [Changelog](https://github.com/celery/billiard/blob/master/CHANGES.txt)
- [Commits](https://github.com/celery/billiard/compare/3.6.1...3.6.2.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
KWierso/treeherder,KWierso/treeherder,KWierso/treeherder,KWierso/treeherder