Pin the version of scikit learn to 1.2.1

pyproject.toml should have exact matching to the classifier it was trained on i.e. scikit-learn == 1.2.1 for v1.1.1.

We still see warning messages. See https://git.ligo.org/emfollow/gwcelery/-/jobs/2623843

UserWarning: Trying to unpickle estimator RandomForestClassifier from version 1.2.1 when using version 1.2.2. This might lead to breaking code or invalid results. Use at your own risk. For more info please refer to:
https://scikit-learn.org/stable/model_persistence.html#security-maintainability-limitations
  warnings.warn(