Modify keyword arguments for Ruby 2.0 compat

Required keyword arguments were introduced in Ruby 2.1, but can be emulated in 2.0 by using a default value that raises an ArgumentError

app/helpers/react_on_rails_helper.rb

@@ -255,8 +255,11 @@ def props_string(props)
 
   # Returns Array [0]: html, [1]: script to console log
   # NOTE, these are NOT html_safe!
-  def server_rendered_react_component_html(props, react_component_name, dom_id,
-                                           prerender:, trace:, raise_on_prerender_error:)
+  def server_rendered_react_component_html(
+    props, react_component_name, dom_id, prerender: raise(ArgumentError, "prerender is required"),
+    trace: raise(ArgumentError, "trace is required"),
+    raise_on_prerender_error: raise(ArgumentError, "raise_on_prerender_error is required")
+  )
     return { "html" => "", "consoleReplayScript" => "" } unless prerender
 
     # On server `location` option is added (`location = request.fullpath`)
@@ -342,7 +345,7 @@ def initialize_redux_stores
   # This is the definitive list of the default values used for the rails_context, which is the
   # second parameter passed to both component and store generator functions.
   # rubocop:disable Metrics/AbcSize
-  def rails_context(server_side:)
+  def rails_context(server_side: raise(ArgumentError, "server_side is required"))
     @rails_context ||= begin
       result = {
         inMailer: in_mailer?,

lib/react_on_rails/react_component/options.rb

@@ -4,7 +4,10 @@ class Options
       NO_PROPS = {}.freeze
       HIDDEN = "display:none".freeze
 
-      def initialize(name:, options:)
+      def initialize(
+        name: raise(ArgumentError, "name is required"),
+        options: raise(ArgumentError, "options are required")
+      )
         @name = name
         @options = options
       end

lib/react_on_rails/test_helper/webpack_assets_status_checker.rb

@@ -9,7 +9,11 @@ class WebpackAssetsStatusChecker
       # client_dir is typically /client, where all client files go
       attr_reader :client_dir, :generated_assets_dir
 
-      def initialize(generated_assets_dir:, client_dir:, webpack_generated_files:)
+      def initialize(
+        generated_assets_dir: raise(ArgumentError, "generated_assets_dir is required"),
+        client_dir: raise(ArgumentError, "client_dir is required"),
+        webpack_generated_files: raise(ArgumentError, "webpack_generated_files is required")
+      )
         @generated_assets_dir = generated_assets_dir
         @client_dir = client_dir
         @webpack_generated_files = webpack_generated_files