(CAT-2397) Unpin puppet_agent

Author: david22swan

.fixtures.yml

@@ -5,9 +5,7 @@ fixtures:
     archive: "https://github.com/voxpupuli/puppet-archive.git"
     augeas_core: "https://github.com/puppetlabs/puppetlabs-augeas_core.git"
     facts: 'https://github.com/puppetlabs/puppetlabs-facts.git'
-    puppet_agent:
-      repo: 'https://github.com/puppetlabs/puppetlabs-puppet_agent.git'
-      ref: v4.21.0
+    puppet_agent: 'https://github.com/puppetlabs/puppetlabs-puppet_agent.git'
     provision: 'https://github.com/puppetlabs/provision.git'
 
   symlinks: