Fix keyword usage for Ruby 3.x support on specs

Author: Jonathan Tapia

spec/controllers/spree/user_registrations_controller_spec.rb

@@ -13,15 +13,15 @@
     let(:password_confirmation) { 'foobar123' }
 
     subject do
-      post(:create, {
+      post(:create,
         params: {
           spree_user: {
             email: '[email protected]',
             password: 'foobar123',
             password_confirmation: password_confirmation
           }
         }
-      })
+      )
     end
 
     context 'when user created successfuly' do

spec/controllers/spree/user_sessions_controller_spec.rb

@@ -10,15 +10,15 @@
     let(:password) { 'secret' }
 
     subject do
-      post(:create, {
+      post(:create,
         params: {
           spree_user: {
             email: user.email,
             password: password
           },
           format: format
         }
-      })
+      )
     end
 
     context "when using correct login information" do