gdk-pixbuf: security bump to version 2.32.3

Fixes:
* Fix two crashes in the bmp loader (#747605, #758991)
* ico: integer overflow fixes

No CVEs assigned yet.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>