Update KDE Plasma Desktop to 5.19.2

Tuesday, 23 June 2020. Today KDE releases a bugfix update to KDE Plasma 5,
versioned 5.19.2. Plasma 5.19 was released in June 2020 with many feature
refinements and new modules to complete the desktop experience.

This release adds a week's worth of new translations and fixes from KDE's
contributors. The bugfixes are typically small but important and include:

• Fix KRunner positioning on X11 with High DPI and Qt scaling on Plasma.
• Fix case of monitored service in startplasma's shutdown.
• KSysGuard: Expose better size hints.

Full changelog:
https://kde.org/announcements/plasma-5.19.1-5.19.2-changelog