Fix example in 06_jupyter-notebook-workflow

[josephhaaga]

Fixes context.catalog.save() example in docs/06_jupyter-notebook-workflow.md.

Looks like the example passes a dict, but pandas.JSONDataSet expects a pandas.DataFrame

Steps to reproduce

my_dict = {"key1": "some_value", "key2": None}
context.catalog.save("my_dataset", my_dict)

Expected

# no errors, dataset saves successfully

Actual

DataSetError: Failed while saving data to data set JSONDataSet(filepath=/Users/josephhaaga/Documents/tmp/testing/data/01_raw/my_dataset.json, load_args={}, protocol=file, save_args={}).
'dict' object has no attribute 'to_json'

[yetudada]

Thanks for this!

[lorenabalan]

Great catch thank you!!