Add a project spec to prevent error when running rake changelog:merge

Follow up rubocop/rubocop@9ddcca4.

Author: koic

spec/project_spec.rb

@@ -173,6 +173,10 @@
         expect(entries).to all(match(/^\* \S/))
       end
 
+      it 'has one space between the period and the parentheses enclosing contributor name' do
+        expect(entries).to all(match(/\. \(\[/))
+      end
+
       describe 'link to related issue' do
         let(:issues) do
           entries.filter_map do |entry|