[bundler/bundler] Be explicit about coloring in specs that need that

https://github.com/bundler/bundler/commit/a4d04506ab

spec/bundler/bundler/source_spec.rb

@@ -65,6 +65,8 @@ RSpec.describe Bundler::Source do
           end
 
           context "without color" do
+            before { Bundler.ui = Bundler::UI::Shell.new("no-color" => true) }
+
             it "should return a string with the spec name and version and locked spec version" do
               expect(subject.version_message(spec)).to eq("nokogiri >= 1.6 (was < 1.5)")
             end