update google-api-client gem

[trinityXmontoya]

• current google-api-client version causes "invalid_grant" error, updating to current version solves this and allows proper service account authorization

[abronte]

Thanks!

[dtaniwaki]

This change broke the compatibility.

See https://github.com/google/google-api-ruby-client/blob/master/MIGRATING.md

@abronte Can you rollback it?

[abronte]

Ah good point. Merged too hastily.