Add given name and family name to identity functions

[asc-ioki]

In their response, google exposes given_name and family_name. See https://developers.google.com/identity/sign-in/web/server-side-flow at the very bottom of the page.

The way I am using google_sign_in, I need access to this data and the cleanest way to get it would be for the gem itself to expose it.

[klaustopher]

Hey there,

I am mentoring @annesc in a project she is currently implementing.

I looked into the failing tests on this PR and this is not caused by anything that @annesc added here. The 2.2 tests are failing because Travis tries to install the current bundler (2.0.1) but that requires a newer Rubygems version. For Ruby 2.2 you have to install an older version of bundler (1.17.3).

Should we add the travis config changes here or in a seperate PR to get the tests passing?

[georgeclaghorn]

Thanks, @klaustopher! We can fix Travis separately.

Sorry for the delay in reviewing. I’ll take a look later today.

[georgeclaghorn]

Thanks, @annesc!

[asc-ioki]

Thank you for including this, @georgeclaghorn!