[4.1-stable] feat: Add IngredientColorSerializer (#157) (#158)

# Backport

This will backport the following commits from `main` to `4.1-stable`:
- [feat: Add IngredientColorSerializer
(#157)](#157)

<!--- Backport version: 9.5.1 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sorenlouv/backport)

Author: tvdeyen

app/serializers/alchemy/json_api/ingredient_color_serializer.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require "alchemy/json_api/ingredient_serializer"
+
+module Alchemy
+  module JsonApi
+    class IngredientColorSerializer < BaseSerializer
+      include IngredientSerializer
+    end
+  end
+end

spec/serializers/alchemy/json_api/ingredient_color_serializer_spec.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe Alchemy::JsonApi::IngredientColorSerializer do
+  let(:ingredient) do
+    Alchemy::Ingredients::Color.new(role: "color", value: "green")
+  end
+
+  subject(:serializer) { described_class.new(ingredient) }
+
+  it_behaves_like "an ingredient serializer"
+
+  describe "attributes" do
+    subject { serializer.serializable_hash[:data][:attributes] }
+
+    it "has the right keys and values" do
+      expect(subject[:value]).to eq("green")
+    end
+  end
+end