Add opnsense 25.1 image (#911)

Closes osism/issues#1243

Signed-off-by: Christian Berendt <berendt@osism.tech>

Author: berendt

etc/images/opnsense.yml

@@ -30,3 +30,8 @@ images:
         mirror_url: https://swift.services.a.regiocloud.tech/swift/v1/AUTH_b182637428444b9aa302bb8d5a5a418c/openstack-images/opnsense/24.1/OPNsense-24.1-nano-amd64.img
         checksum: "sha256:149641d45243bdbd7da3527408f31c3c4b02b5c6ca29b261b10c9af4236d11e7"
         build_date: 2024-01-29
+      - version: '25.1'
+        url: https://mirror.ams1.nl.leaseweb.net/opnsense/releases/25.1/OPNsense-25.1-nano-amd64.img.bz2
+        mirror_url: https://swift.services.a.regiocloud.tech/swift/v1/AUTH_b182637428444b9aa302bb8d5a5a418c/openstack-images/opnsense/25.1/OPNsense-25.1-nano-amd64.img
+        checksum: "sha256:794a4d09846a974d0d041a0235ef29f54954e47843164912d46899016e0865a1"
+        build_date: 2025-01-28