Hints for openscad in main

Warnings

• asv-mimetypes-tag-deprecated
  :24 -
  The toplevel `mimetypes` tag is deprecated. Please use `mediatype` tags in a `provides` block instead to indicate that your software provides a media handler for the given types.
• asv-releases-not-in-order
  - 2015.03 << 2019.05
  The releases are not sorted in a latest to oldest version order. This is required as some tools will assume that the latest version is always at the top. Sorting releases also increases overall readability of the metainfo file.