fstring needs fix

[joamatab]

missing f in fstring in line 200 in netlist.py

~/mambaforge/lib/python3.10/site-packages/sax/netlist.py in _model_operations(models, ops, default_models)
    198 
    199         if "model" not in model:
--> 200             raise ValueError(
    201                 "Invalid model dict for '{component}'. Key 'model' not found."
    202             )

ValueError: Invalid model dict for '{component}'. Key 'model' not found.

this should be

raise ValueError(
    201                 f"Invalid model dict for '{component}'. Key 'model' not found."
    202             )

[flaport]

Done.