Make the manifest import feature spec a postgres only

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

spec/features/import/manifest_import_spec.rb

 require 'spec_helper'
 
-feature 'Import multiple repositories by uploading a manifest file', :js do
+feature 'Import multiple repositories by uploading a manifest file', :js, :postgresql do
   include Select2Helper
 
   let(:user) { create(:admin) }