Changes

• Add wait_finished method to jobs class, which blocks until a specified job is finished (#242 by @JonaOtto)
• fix some typos (#243 by @schluenz)
• fix not being able to create RPMs with bdist_rpm (#248)
• fix formatting erros, add end_time to slurm_update_reservation and raise a proper ValueError when updating the reservation fails (#257, #256, #255 by @pllopis)
• actually retrieve and return the batch script as a string, instead of just printing it (#258)
• bring possible RPC strings in sync with slurm 22.05 when getting Slurm statistics via the statistics class (#261 by @wresch)