Maintenance release: Godot 3.4.3

In parallel to our work on the upcoming feature releases Godot 3.5 (with a first beta) and 4.0 (now at alpha 3!), we backport important fixes to the stable 3.4 branch for use in production.

A number of such fixes have been queued in the two months since the 3.4.2 release, and we after a couple of Release Candidates (thanks to all testers!), we're now ready to release Godot 3.4.3-stable as a maintenance update to the current stable branch.

Read the release blog post for details on the changes.