imageprofile: bump default OpenWRT version to 25.12

Author: Noki

group_vars/all/imageprofile.yml

@@ -1,6 +1,6 @@
 ---
 # default OpenWRT version to build from unless overridden
-openwrt_version: 24.10-SNAPSHOT
+openwrt_version: 25.12-SNAPSHOT
 
 # openwrt_mirror: https://downloads.openwrt.org
 openwrt_mirror: https://mirror.berlin.freifunk.net/downloads.openwrt.org