jobs/master-builds: use debian-bullseye-jenkins

I've verified that all master-builds jobs still work with this change.

Related: OS#5949
Depends: docker-playground I51925d0ab9e5a779379efab59c381ef12fb60929
Change-Id: I7d5bc7bb4c1457d4e05fd6e0d27668382c39973a
---
M jobs/master-builds.yml
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/jobs/master-builds.yml b/jobs/master-builds.yml
index 008452a..23e5219 100644
--- a/jobs/master-builds.yml
+++ b/jobs/master-builds.yml
@@ -63,7 +63,7 @@
               -e CCACHE_DIR="/ccache" \
               -e PATH="/usr/lib/ccache:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" \
               -v "$CCACHE_DIR:/ccache" \
-    docker_img: '$USER/debian-buster-jenkins'
+    docker_img: '$USER/debian-bullseye-jenkins'
     timeout_cmd: '/usr/bin/timeout 30m'
     cmd: '{docker_run_ccache} {docker_img} {timeout_cmd} /build/contrib/jenkins.sh'
     trigger:

