CI: remove 'v' prefix in assets

Fixed issue anrieff#105: New Release version

The version is 0.4.1 (instead of suggested 0.5.0) since it
introduces no backwards-incompatible changes.

Only version is actually changed, no code modifications.

Fixed issue anrieff#78: date in changelog is wrong

Update the release date for 0.3.0 in the ChangeLog.

Add ucbench to the users list.

Fix tests due to X0rg's codename changes.