Bump pip-tools from 5.5.0 to 6.0.0 in /python/helpers

Bumps [pip-tools](https://github.com/jazzband/pip-tools) from 5.5.0 to 6.0.0.
- [Release notes](https://github.com/jazzband/pip-tools/releases)
- [Changelog](https://github.com/jazzband/pip-tools/blob/master/CHANGELOG.md)
- [Commits](jazzband/pip-tools@5.5.0...6.0.0)

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

python/helpers/requirements.txt

@@ -1,5 +1,5 @@
 pip==20.3.3
-pip-tools==5.5.0
+pip-tools==6.0.0
 flake8==3.8.4
 hashin==0.15.0
 pipenv==2018.11.26