Datetime parsing in shakemaps_from_quakeml

Currently there is a problem on processing some of the events from geofon with the shakemaps_from_quakeml workflow.

This effects for example the following event:

• gfz2021kdvq
• gfz2021keus

Traceback is the following:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/src/app/shakyground2/shakyground2/workflows.py", line 93, in shakemaps_from_quakeml
    results.earthquake = Earthquake.from_quakeml(event_id)
  File "/usr/src/app/shakyground2/shakyground2/earthquake.py", line 219, in from_quakeml
    d_t = datetime.datetime.fromisoformat(" ".join([event["date"], event_time]))
ValueError: Invalid isoformat string: '2021-05-25 09:41:17.20'