ci: use Debian Trixie based service container

Recently, our Linux development swited to Debian Trixie, so we should
migrate our test, too.

Signed-off-by: Patrick Bruenn <p.bruenn@beckhoff.com>

Author: pbruenn

Dockerfile

@@ -1,6 +1,6 @@
 ARG REGISTRY_HOST
 ARG BHF_CI_ARCH
-FROM ${REGISTRY_HOST}/beckhoff/test-tcos/tc31-xar-um:master-${BHF_CI_ARCH}
+FROM ${REGISTRY_HOST}/beckhoff/test-tcos/tc31-xar-um:bhf-13-trixie-${BHF_CI_ARCH}
 ARG BHF_CI_ARCH
 COPY tools/TwinCAT/3.1 /etc/TwinCAT/3.1
 COPY PLC-TestProject/_Boot-${BHF_CI_ARCH} /etc/TwinCAT/3.1/Boot