buildroot

package/rauc: Version bump to 0.3

There's a bug in 0.2 which prevents proper operation when activated via
D-Bus, which is why I'm bumping this.

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://github.com/rauc/rauc/issues/125
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>