import statement update train_test_split

[WilliamLage]

noted that in the chapter one oner_application code you're using an outdated import statement for sklearn's train_test_split function. please update as follows to comply with sklearn version 0.24.1

existing code
from sklearn.cross_validation import train_test_split

please update to
from sklearn.model_selection import train_test_split

the code runs fine after that amendment, but as this is likely in other notebooks in this publication it will require changes in subsequent files barring users who practice version control.