Hints for cambalache in main

Warnings

• asv-tag-empty
  ar.xjuan.Cambalache.metainfo.xml:341 - ul/li
  The mentioned tag is empty, which is highly likely not intended as it should have content.
• asv-description-has-plaintext-url
  ar.xjuan.Cambalache.metainfo.xml:604 - ul
  The description contains a web URL in plain text. This is not allowed, please use the <url/> tag instead to share links.