docs: older version of Ansible needed for RHEL 8 (#4124)

Update our Ansible documentation to note that newer versions of Ansible
are not compatible with RHEL 8 and provide the last known back-level
compatible versions of `ansible` and `ansible-core` that work.

Refs: https://forum.ansible.com/t/almalinux-and-python3-dnf/44262/4
Refs: https://forum.ansible.com/t/python-3-7-impact-on-el8-future-for-el9/6229/13

Author: richardlau

ansible/README.md

@@ -7,6 +7,10 @@
 
 1. Follow the [instructions to install the latest version of Ansible][ansible-install].
    * In most cases, using pip: `pip install ansible`.
+     * Newer versions of Ansible are incompatible with some older operating systems in the inventory (e.g. RHEL 8). In those cases you will need to install an older version of Ansible, e.g. if using `pip`:
+      ```console
+      pip install ansible-core==2.16.14 ansible==9.13
+      ```
    * If you use brew, then `brew install python3 ansible`, and then run
    `export PYTHONPATH=$(pip show pyyaml | grep Location | awk '{print $2}') `
    before you use `ansible-playbook`.