Hints for godot3 in main

Hints

• asv-developer-name-tag-deprecated
  org.godotengine.Godot3.metainfo.xml:34 -
  The toplevel `developer_name` element is deprecated. Please use the `name` element in a `developer` block instead.
• asv-content-rating-missing
  org.godotengine.Godot3.metainfo.xml -
  This component has no `content_rating` tag to provide age rating information. You can generate the tag data online by answering a few questions at https://hughsie.github.io/oars/
• asv-developer-info-missing
  org.godotengine.Godot3.metainfo.xml -
  This component contains no `developer` element with information about its author.