Bump cython from 0.29.34 to 3.0.0 in /python/helpers

Bumps [cython](https://github.com/cython/cython) from 0.29.34 to 3.0.0.
- [Release notes](https://github.com/cython/cython/releases)
- [Changelog](https://github.com/cython/cython/blob/master/CHANGES.rst)
- [Commits](cython/cython@0.29.34...3.0.0)

---
updated-dependencies:
- dependency-name: cython
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

python/helpers/requirements.txt

@@ -7,4 +7,4 @@ poetry>=1.1.15,<1.6.0
 wheel==0.37.1
 
 # Some dependencies will only install if Cython is present
-Cython==0.29.34
+Cython==3.0.0