v3.4

• A couple of major bugfixes (parallel MCMC chains getting stuck; issues when resuming).
• Easier loading and MPI sharing of SampleCollections and sampler products, including native GetDist conversion.
• Python 3.12 support.
• Added 1-d grid LSS likelihood and BAO-only ELG and QSO (@msyriac)
• Some CLASS-related minor updates.