chore(deps): bump pytorch-lightning from 1.2.3 to 1.2.4

Bumps [pytorch-lightning](https://github.com/PyTorchLightning/pytorch-lightning) from 1.2.3 to 1.2.4.
- [Release notes](https://github.com/PyTorchLightning/pytorch-lightning/releases)
- [Changelog](https://github.com/PyTorchLightning/pytorch-lightning/blob/1.2.4/CHANGELOG.md)
- [Commits](Lightning-AI/pytorch-lightning@1.2.3...1.2.4)

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