Update to release 18.05 and rebased shotcut-noupdatecheck.patch.
Upstream changes:
*Added Keyframe support with a new Keyframes panel.
*Added 5.1 Surround Sound.
*Added Finnish translation.
*Restored GIF Animation for Export.
*Reduced memory footprint (especially for the Rotate and Size and
Position filters).
*Changed default Export settings to reduce output size by
increasing GOP and number of B frames.
*See https://shotcut.org/blog/new-release-1805/