Update pytorch-lightning requirement

Updates the requirements on [pytorch-lightning](https://github.com/Lightning-AI/lightning) to permit the latest version.
- [Release notes](https://github.com/Lightning-AI/lightning/releases)
- [Commits](Lightning-AI/pytorch-lightning@1.8.0...2.1.3)

---
updated-dependencies:
- dependency-name: pytorch-lightning
  dependency-type: direct:production
...

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

requirements.txt

@@ -3,7 +3,7 @@ category-encoders >=2.6.0, <2.7.0
 numpy >=1.17.2
 pandas >=1.1.5
 scikit-learn >=1.0.0
-pytorch-lightning>=1.8.0, <2.0.0
+pytorch-lightning>=1.8.0, <3.0.0
 omegaconf >=2.1.0
 torchmetrics >=0.10.0, <0.12.0
 tensorboard >2.2.0, !=2.5.0