Fix missing switch from key to attribute access in xfel-calibrate args after rework

Looks like this key access to command line arguments was missed when rebasing https://git.xfel.eu/detectors/pycalibration/-/merge_requests/575

@kluyvert

changed milestone to %3.5.0

added Waiting for review label

requested review from @kluyvert

The change LGTM. Unfortunately the tests are failing, presumably for reasons unrelated to the change. I'm guessing some of the data the tests expect in the test calcat instance has been removed.

Yes, the pipeline keep failing left and right due to this. I'll take a look later. Thanks for review!

merged

mentioned in commit 85605a4b

removed Waiting for review label