Lint: Fix Money spec

Rubocop was understandably not happy about comparing very obviously
identical things, so I've made it less obvious by creating a new,
identical object.

.rubocop_todo.yml

@@ -213,11 +213,6 @@ Lint/AmbiguousOperator:
     - "bin/rails-application-template"
     - "bin/rspec"
 
-# Offense count: 1
-Lint/BinaryOperatorWithIdenticalOperands:
-  Exclude:
-    - "core/spec/lib/spree/money_spec.rb"
-
 # Offense count: 43
 # Configuration parameters: AllowedMethods.
 # AllowedMethods: enums

core/spec/models/spree/money_spec.rb

@@ -243,10 +243,11 @@
   describe "<=>" do
     let(:usd_10) { Spree::Money.new(10, currency: "USD") }
     let(:usd_20) { Spree::Money.new(20, currency: "USD") }
+    let(:other_usd_20) { Spree::Money.new(20, currency: "USD") }
     let(:usd_30) { Spree::Money.new(30, currency: "USD") }
 
     it "compares the two amounts" do
-      expect(usd_20 <=> usd_20).to eq 0
+      expect(usd_20 <=> other_usd_20).to eq 0
       expect(usd_20 <=> usd_10).to be > 0
       expect(usd_20 <=> usd_30).to be < 0
     end