AlphaPulldown v2.0.0b4

1. Merged updated manual, credits to @gilep
2. Fixed bug: predictions for homo-oligomers using whole ranges.
3. ranking_debug.json: save iptm for multimers OR ptm for monomers.
4. Added modelcif dependency to the pulldown.docker file and github actions.
5. Used system.entities instead of system.target_entities for convert_to_modelcif.py.
6. Added tests for modelcif and run_multimer_jobs.py.
7. Used the correct docker image from kosinskilab for the analysis pipeline.