Mesa 12.0.6 is released

Mesa 12.0.6 is released. This is a bug-fix release.

Note
This is an extra release for the 12.0 stable branch, as per developers' feedback. It is anticipated that 12.0.6 will be the final release in the 12.0 series. Users of 12.0 are encouraged to migrate to the 13.0 series in order to obtain future fixes.