pin puppet-pulpcore to a version that supports EL8 for 3.39/3.49

Author: evgeni

pipelines/vars/forklift_pulpcore.yml

@@ -6,3 +6,5 @@ server_box:
 
 forklift_boxes:
   "{{ {forklift_name: server_box} }}"
+
+beaker_puppet_module_version: "{{ '11.0.0' if pipeline_version in ['3.39', '3.49'] else 'HEAD' }}"