Add FactoryBot definition for organisation_name_change

spec/factories/organisation_name_change.rb

@@ -0,0 +1,18 @@
+FactoryBot.define do
+  factory :organisation_name_change do
+    association :organisation
+    name { "#{Faker::Name.name} Housing Org" }
+    immediate_change { true }
+    startdate { Time.zone.now }
+    change_type { :user_change }
+
+    trait :future_change do
+      immediate_change { false }
+      startdate { 5.days.from_now }
+    end
+
+    trait :merge_change do
+      change_type { :merge }
+    end
+  end
+end