package/xmrig: bump version to 6.21.2
Changelog: https://github.com/xmrig/xmrig/blob/master/CHANGELOG.md
Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit c8800c34feef5f6df2220a6e704517d6fe4baa91)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>