Remove unnecessary detail about omniauth
Remove unnecessary detail about omniauth

Co-authored-by: Ben Thorner <90b91a8305da3dfd8069e2ed1b938f1452d09955@users.noreply.github.com>

alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs