Removing unnecesary pin

Author: LukasAud

.fixtures.yml

@@ -6,7 +6,6 @@ fixtures:
     provision: "https://github.com/puppetlabs/provision.git"
     puppet_agent:
       repo: 'https://github.com/puppetlabs/puppetlabs-puppet_agent.git'
-      ref: v4.25.0
     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"