Update unexpected-documentation-site-generator to ^4.2.3

package.json

@@ -44,7 +44,7 @@
     "serve": "*",
     "sinon": "1.17.5",
     "unexpected": "10.16.0",
-    "unexpected-documentation-site-generator": "^4.0.0",
+    "unexpected-documentation-site-generator": "^4.2.3",
     "unexpected-markdown": "1.4.1"
   }
 }