(CAT-2100) Add debian-12 support

Author: shubhamshinde360

.fixtures.yml

@@ -4,7 +4,7 @@ fixtures:
     provision: 'https://github.com/puppetlabs/provision.git'
     puppet_agent: 
       repo: 'https://github.com/puppetlabs/puppetlabs-puppet_agent.git'
-      ref: v4.13.0
+      ref: v4.21.0
     registry: 'https://github.com/puppetlabs/puppetlabs-registry.git'
     stdlib: 'https://github.com/puppetlabs/puppetlabs-stdlib.git'
   symlinks:

metadata.json

@@ -49,7 +49,8 @@
       "operatingsystem": "Debian",
       "operatingsystemrelease": [
         "10",
-        "11"
+        "11",
+        "12"
       ]
     },
     {