KDE: Update KDE Gear to 23.08.1

Thursday, 14 September 2023. Over 120 individual programs plus dozens of
programmer libraries and feature plugins are released simultaneously as
part of KDE Gear.

Today they all get new bugfix source releases with updated translations,
including:

• gwenview: Fix navigation with side mouse buttons
• kio-extras: Thumbnail: Fix heap-use-after-free in AudioCreator::create
• akonadi-calendar: Use correct identity when sending iTIP counter-proposal

Changelog: https://kde.org/announcements/changelogs/gear/23.08.1/