Use keyword argument for options

> Keyword arguments are separated from other arguments.

From: https://www.ruby-lang.org/en/news/2020/12/25/ruby-3-0-0-released/

lib/ember_cli/configuration.rb

@@ -8,7 +8,7 @@ class Configuration
     attr_accessor :watcher
 
     def app(name, **options)
-      app = App.new(name, options)
+      app = App.new(name, **options)
       apps.store(name, app)
     end
 

spec/generators/ember/heroku/heroku_generator_spec.rb

@@ -106,8 +106,8 @@ def package_json_contents
     end
   end
 
-  def configure_application(options = {})
-    EmberCli.configure { |c| c.app("my-app", options) }
+  def configure_application(**options)
+    EmberCli.configure { |c| c.app("my-app", **options) }
   end
 
   def setup_destination

spec/lib/ember_cli/command_spec.rb

@@ -111,6 +111,6 @@ def build_paths(**options)
   end
 
   def build_command(**options)
-    EmberCli::Command.new(options)
+    EmberCli::Command.new(**options)
   end
 end

spec/lib/ember_cli/path_set_spec.rb

@@ -364,7 +364,7 @@ def stub_which(program_to_path)
 
   def build_path_set(**options)
     EmberCli::PathSet.new(
-      options.reverse_merge(
+      **options.reverse_merge(
         app: build_app,
         rails_root: rails_root,
         ember_cli_root: ember_cli_root,