Update python client to version 3.0.0 from 1.3.0
Update python client to version 3.0.0 from 1.3.0

gov-cjwaszczuk/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin,gov-cjwaszczuk/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin,gov-cjwaszczuk/notifications-admin,gov-cjwaszczuk/notifications-admin