Bump omniauth from 1.3.1 to 1.8.1
Bump omniauth from 1.3.1 to 1.8.1

Bumps [omniauth](https://github.com/omniauth/omniauth) from 1.3.1 to 1.8.1.
- [Release notes](https://github.com/omniauth/omniauth/releases)
- [Commits](https://github.com/omniauth/omniauth/compare/v1.3.1...v1.8.1)
FundingCircle/shipment_tracker,FundingCircle/shipment_tracker,FundingCircle/shipment_tracker,FundingCircle/shipment_tracker