[AppStream] AppStream 0.15.4 released!

[Matthias Klumpp]

Hi!
A new AppStream release has been done, containing mostly bugfixes and
validator check enhancement and compose improvements.

Tarballs available here:
https://www.freedesktop.org/software/appstream/releases/

Cheers,
    Matthias

Version 0.15.4
~~~~~~~~~~~~~~
Released: 2022-05-22

Features:
 * validator: Check timestamp validity
 * validator: Allow (limited) overriding of issue tag severities
 * validator: Add strict mode
 * ascli: validate: Allow simple overriding of issue tags
 * validator: Check for exact relation item redefinitions

Bugfixes:
 * Add vcs-browser URL to metainfo.xml
 * compose: Improve media-baseurl sanity checks for icon/screenshot policies
 * compose: Don't create bad data when localized screenshots exist
 * compose: Sanitize prefix value and verify all units for results
 * compose: Fail and not just warn if we couldn't open a unit
 * compose: Make no-result detection a bit more robust
 * compose: Properly handle localized screenshots
 * compose: Ignore current locale when analyzing screencasts

Contributors:
 JakobDev, Matthias Klumpp