Stop using rails method #with_indifferent_access
Stop using rails method #with_indifferent_access

Although gds-api-adapters is being used in Rails apps at the moment, Rails is
not listed as a dependency. This replaces the use of with_indifferent_access
with deep_transform_keys to convert keys to symbols, or deep_stringify_keys to
convert them to strings.

alphagov/gds-api-adapters