BUG: Fix read_csv on S3 files for python 3
Closes https://github.com/pydata/pandas/issues/9452

Needed to pass along encoding parameter.

No tests... Kind of hard since it's only s3 only.

Looks like there was already an existing test for reading from S3 :).
 Good thing too! I was going to test this at work on py2, so I would have caught it :)
 The failure cam from us using an old version of boto. The `encoding` parameter was added since 2.26.1. I bumped the version for our tests to the latest (2.36.0).
 thanks @TomAugspurger 
