Make documentation Python 3.7 compliant

[petervandenabeele]

The documentation on the welcome page states

https://pypi.org/project/python-digitalocean/

actions = droplet.get_actions()
for action in actions:
    action.load()
    # Once it shows complete, droplet is up and running
    print action.status

It took me a bit of time before I realized the parenthesis for print are missing ...

=> print (action.status)

Thanks :-)