SPARKX requires Python 3.9, but requirements states 3.8

[NGoetz]

Traceback (most recent call last):
File "/impact_parameter_plotting_script.py", line 11, in
import sparkx
File "/python3.8/site-packages/sparkx/init.py", line 10, in
from sparkx.EventCharacteristics import EventCharacteristics
File "//python3.8/site-packages/sparkx/EventCharacteristics.py", line 17, in
class EventCharacteristics:
File "//python3.8/site-packages/sparkx/EventCharacteristics.py", line 75, in EventCharacteristics
np.ndarray[Any, np.dtype[np.object_]]]
TypeError: Type subscription requires python >= 3.9

We should either not use that functionality or update the requirements.