manibuilder/alpine: Add official multi-arch tags for 3.15, 3.16 and 3.17

Change-Id: Ib587f5f0e1e21b662265b9cf17b982fc2daf5e1c
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/73434
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
1 file changed