allow googleads to install alongside google-auth 2.x

[Michael Greene]

currently you have google-auth pinned to be 1.x:

'google-auth>=1.0.0,<2.0.0'

google-auth has been stable above 2.0 for 7 months: https://pypi.org/project/google-auth/#history

I have lightly tested googleads 27.0.0 and 31.0.0 with google-auth 2.6.3 and it seems like it works, any chance the version requirement could be widened to allow 2.x as well?

[Chris Seeley]

Fixed in v35.0+