Fix excessive latency with Vulkan video decoding on Nvidia

For yet unknown reasons, high frame queue delay leads to massive decode latency.

Fix changelog typo

Prepare for v6.0.0

Fix CUDA build without KMSDRM enabled

Bump release date in appstream

Update v4.3.1 changelog

Bump v4.3.0 release date

Prepare for v4.2.1

Prepare for v4.2.0

Draw the black background even for the KMSDRM backend to fix modesetting