Release 0.6.8

0.6.8 - 2024-04-05

Changed

• Updated celery from buggy 5.3.1 that would feed gradients to parallel_hessian in random orders causing the wrong gradients to be applied to the wrong atoms. Now using ^5.3.4 which fixes this issue.
• Tightened many >= package dependencies to more tight ^ dependencies to avoid breaking changes in the future.
• Changed tests for parallel_hessian and parallel_frequency_analysis to test for correctness of the results rather than just that the function runs without error. This would capture a future regression where celery returns results in the wrong order.
• Updated all dependencies to the latest versions. (poetry update)