Drop support for CentOS, test Rocky and Debian in CI (#92)

* Test CentOS 7 in CI

* Drop support for CentOS, test on Rocky and Debian

* Fix reset playbook for Rocky Linux

* Fix typo

* Disable firewalld during testing

Co-authored-by: Techno Tim <timothystewart6@gmail.com>

README.md

@@ -16,9 +16,9 @@ If you want more context on how this works, see:
 
 Build a Kubernetes cluster using Ansible with k3s. The goal is easily install a HA Kubernetes cluster on machines running:
 
-- [X] Debian
-- [X] Ubuntu
-- [X] CentOS
+- [x] Debian (tested on version 11)
+- [x] Ubuntu (tested on version 22.04)
+- [x] Rocky (tested on version 9)
 
 on processor architecture: