Bump cython from 0.29.35 to 3.0.8 in /rastervision_pytorch_learner

Bumps [cython](https://github.com/cython/cython) from 0.29.35 to 3.0.8.
- [Release notes](https://github.com/cython/cython/releases)
- [Changelog](https://github.com/cython/cython/blob/master/CHANGES.rst)
- [Commits](cython/cython@0.29.35...3.0.8)

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

Signed-off-by: dependabot[bot] <[email protected]>

rastervision_pytorch_learner/requirements.txt

@@ -6,7 +6,7 @@ torch==2.1.2
 torchvision==0.16.2
 tensorboard==2.15.1
 albumentations==1.3.1
-cython==0.29.35
+cython==3.0.8
 pycocotools==2.0.7
 psutil==5.9.3
 opencv-python-headless==4.9.0.80