Update ha repository name for CentOS 8

Since CentOS 8.3 repository name has changed from HighAvailability to just ha.
We need to reflect this as well

Author: Dmitriy Rabotyagov

tasks/pacemaker.yml

@@ -1,5 +1,5 @@
 - name: Enable HighAvailability repository
-  command: yum-config-manager --enable HighAvailability
+  command: yum-config-manager --enable ha
   changed_when: false
   when:
     - ansible_os_family | lower == 'redhat'