Flatpak version is using EOL stack

[Nyalnara]

Before posting

Please follow the steps below and check the boxes with [x] once you did the step.

• I checked the issue tracker for similar issues
• I checked the changelog if the issue is already resolved
  (Third check doesn't apply to this case.)

System information

Please provide information about your system and the version of Clementine used.

• Operating System: EndeavourOS Linux x86_64 (arch-based distro)
• Clementine version: Clementine Flatpak latest version (Version 1.4 rc2)

Expected behaviour / actual behaviour

Flatpak version is using EOL versions of org.kde.Platform and org.freedesktop.Platform.GL.default (see flatpak output below for details), would be greatly appreciated to have those updated to something recent, if possible.

[nyalnara@nyalnara-endeavouros ~]$ flatpak update
Looking for updates…

Info: runtime org.kde.Platform branch 5.15-21.08 is end-of-life, with reason:
   We strongly recommend moving to the latest stable version of the Platform and SDK
Info: applications using this runtime:
   org.clementine_player.Clementine

Info: runtime org.freedesktop.Platform.GL.default branch 21.08 is end-of-life, with reason:
   org.freedesktop.Platform 21.08 is no longer receiving fixes and security updates. Please update to a supported runtime version.
Info: applications using this extension:
   org.clementine_player.Clementine

Nothing to do.

[wilx]

Related: flathub/org.clementine_player.Clementine#117