B008 fails for function calls within expressions

[adamchainz]

B008 does not detect cases where function calls are used in sub-expressions, like:

import datetime as dt

def f(when=dt.datetime.now() + dt.timedelta(days=7)):
    pass

[jpy-git]

Makes sense, I've got a fix for this so will tidy it up and make the PR later today 👍

[adamchainz]

Brilliant, thanks!