Hints for gamehub in main

Hints

• asv-description-first-para-too-short
  com.github.tkashkin.gamehub.appdata.xml:12 - Manage your Steam, GOG and Humble Bundle games in one place.
  The first `description/p` paragraph of this component might be too short (< 80 characters). Please consider starting with a longer paragraph to improve how the description looks like in software centers and to provide more detailed information on this component immediately in the first paragraph.
• asv-developer-name-tag-deprecated
  com.github.tkashkin.gamehub.appdata.xml:15 -
  The toplevel `developer_name` element is deprecated. Please use the `name` element in a `developer` block instead.
• asv-developer-info-missing
  com.github.tkashkin.gamehub.appdata.xml -
  This component contains no `developer` element with information about its author.