Merge pull request #669 from puppetlabs/pdksync_(MAINT)_Pin_puppetlabs-puppet_agent

pdksync - (CONT-768) Pin puppetlabs-puppet_agent

Author: LukasAud

.fixtures.yml

@@ -4,7 +4,9 @@ fixtures:
     facts: 'https://github.com/puppetlabs/puppetlabs-facts.git'
     "stdlib": "https://github.com/puppetlabs/puppetlabs-stdlib.git"
     provision: "https://github.com/puppetlabs/provision.git"
-    puppet_agent: 'https://github.com/puppetlabs/puppetlabs-puppet_agent.git'
+    puppet_agent:
+      repo: 'https://github.com/puppetlabs/puppetlabs-puppet_agent.git'
+      ref: v4.12.1
     package: "https://github.com/puppetlabs/puppetlabs-package.git"
     deploy_pe: "https://github.com/jarretlavallee/puppet-deploy_pe"
     sign_cert: "https://github.com/m0dular/sign_cert"