Pin further Chemformer dependencies to avoid torch reinstallation

[kmaziarz]

Recently, the CI stopped working, as pip-installing syntheseus[all] started triggering a reinstallation of torch, despite the fact that we explicitly set up the right version of torch in the base environment (defined in environment_full.yml). A few weeks ago this was not the case (compare successful CI run two weeks ago vs failed one yesterday). This is caused by torchmetrics having been recently updated to 1.6.0; despite the fact that syntheseus-chemformer pins its pytorch-lightning dependency, the latter seemingly doesn't pin torchmetrics, as we started getting the new version after it was released, which in turn is not compatible with the version of torch we use, prompting a reinstallation, and causing other dependencies (notably torch-scatter) to end up in a broken state. The solution here is to add a pin for torchmetrics, which I've done in the syntheseus-chemformer package and released as 0.2.0.

[AustinT]

Thanks detective Maziarz! Looks good 🕵️