package/v4l2loopback: security bump to version 0.12.7

Fix CVE-2022-2652: Depending on the way the format strings in the card
label are crafted it's possible to leak kernel stack memory. There is
also the possibility for DoS due to the v4l2loopback kernel module
crashing when providing the card label on request (reproduce e.g. with
many %s modifiers in a row).

https://github.com/umlaeute/v4l2loopback/blob/v0.12.7/ChangeLog



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>