Update moto to 1.x milestone version

[dlstadther]

Description

Update moto version from 0.x milestone version to 1.x.

Motivation and Context

Updating moto is a step in the direction of verifying/updating Luigi for Python 3.7.0.

There might be breaking changes (as noted by moto 1.0.0).

Related to #2466

Have you tested this? If so, how?

Letting Travis do this.

[dlstadther]

To avoid scrolling back through the errors: py27-nonhdfs:

ERROR: test_read_iterator_long (contrib.s3_test.TestS3Target)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/build/spotify/luigi/test/contrib/s3_test.py", line 106, in test_read_iterator_long
    lines = [line for line in read_file]
  File "/home/travis/build/spotify/luigi/luigi/contrib/s3.py", line 607, in __iter__
    chunk = next(key_iter)
  File "/home/travis/build/spotify/luigi/luigi/contrib/s3.py", line 85, in read
    return self.streaming_body.read(size)
  File "/home/travis/build/spotify/luigi/.tox/py27-nonhdfs/lib/python2.7/site-packages/botocore/response.py", line 76, in read
    chunk = self._raw_stream.read(amt)
  File "/home/travis/build/spotify/luigi/.tox/py27-nonhdfs/lib/python2.7/site-packages/urllib3/response.py", line 413, in read
    data = self._fp.read(amt)
  File "/opt/python/2.7.14/lib/python2.7/StringIO.py", line 127, in read
    _complain_ifclosed(self.closed)
  File "/opt/python/2.7.14/lib/python2.7/StringIO.py", line 40, in _complain_ifclosed
    raise ValueError, "I/O operation on closed file"
ValueError: I/O operation on closed file

[dlstadther]

@Tarrasch Is this adequate validation that the next milestone version of moto works for us?

Only 1 test failed, originally. The issue appeared to be due to the lack of a final new line. The addition of the aforementioned NL corrected the test.

[Tarrasch]

Nice fix! Thanks for doing this!