install_puppet workflow: add Debian 12 to install-puppet job

Author: kenyon

.github/workflows/install_puppet.yaml

@@ -20,6 +20,7 @@ jobs:
           { name: "CentOS 7", image: "litmusimage/centos:7" },
           { name: "Debian 10", image: "litmusimage/debian:10" },
           { name: "Debian 11", image: "litmusimage/debian:11" },
+          { name: "Debian 12", image: "litmusimage/debian:12" },
           { name: "Ubuntu 18.04", image: "litmusimage/ubuntu:18.04" },
           { name: "Ubuntu 20.04", image: "litmusimage/ubuntu:20.04" },
           { name: "Ubuntu 22.04", image: "litmusimage/ubuntu:22.04" },