Change method used to retrieve rack status (#1457) (#1463)

Fixes #1456

Co-authored-by: pareeohnos <adrian@euphoricpanda.co.uk>
Co-authored-by: Adrian Hooper <adrian.hooper@builder.ai>

lib/jsonapi/error.rb

@@ -15,7 +15,7 @@ def initialize(options = {})
       @source         = options[:source]
       @links          = options[:links]
 
-      @status         = Rack::Utils::SYMBOL_TO_STATUS_CODE[options[:status]].to_s
+      @status         = Rack::Utils.status_code(options[:status]).to_s
       @meta           = options[:meta]
     end
 
@@ -46,7 +46,7 @@ def update_with_overrides(error_object_overrides)
 
       if error_object_overrides[:status]
         # :nocov:
-        @status         = Rack::Utils::SYMBOL_TO_STATUS_CODE[error_object_overrides[:status]].to_s
+        @status         = Rack::Utils.status_code(error_object_overrides[:status]).to_s
         # :nocov:
       end
       @meta           = error_object_overrides[:meta] || @meta