license-list-XML as submodule and further monkeypatch licensee to use it

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "license-list-XML"]
+	path = license-list-XML
+	url = https://github.com/spdx/license-list-XML.git

_config.yml

@@ -34,6 +34,7 @@ exclude:
   - assets/vendor/selectivizr/tests
   - assets/vendor/clipboard/test
   - assets/vendor/*/README.*
+  - license-list-XML
 
 plugins:
   - jekyll-sitemap

license-list-XML

@@ -0,0 +1 @@
+Subproject commit b7470fcd383d59c95187af07b66b926e4ca23201

spec/spec_helper.rb

@@ -139,6 +139,9 @@ module Licensee
         dir = ::File.dirname(__FILE__)
         ::File.expand_path '../_licenses', dir
       end
+      def spdx_dir
+        ::File.expand_path '../license-list-XML/src', __dir__
+      end
     end
   end
 end