Roll new release with preference for new google-auth library.

[bjwatson]

This still uses oauth2client by default, but will use
https://pypi.python.org/pypi/google-auth if installed.

Set upper bounds on dependencies to avoid future surprises.

FYI @jonparrott @dhermes

[theacodes]

👍

[codecov-io]

Current coverage is 97.96% (diff: 100%)

Merging #140 into master will not change coverage

@@             master       #140   diff @@
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  Files             9          9          
  Lines           640        640          
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
  Hits            627        627          
  Misses           13         13          
  Partials          0          0          

Powered by Codecov. Last update 62170e4...8173dee

[geigerj]

Note that we should not update the packman configuration until GAPIC has also been updated to use the new auth surface.

[bjwatson]

@geigerj Do you see any problems with updating packman to use this version, as long as it does not add a google-auth dependency?

[geigerj]

@bjwatson Yes, there's a problem -- #135 changed the public interface of GAX, so codegen needs some superficial updates before it can depend on GAX 0.15.0. I can do that tomorrow and then update packman if that works?

[bjwatson]

SGTM