Update RHEL repo for Ansible 2.8 (#56859) (#56868)

(cherry picked from commit 3129fc0b17)

docs/docsite/rst/installation_guide/intro_installation.rst

@@ -113,13 +113,19 @@ On RHEL and CentOS:
 
     $ sudo yum install ansible
 
-RPMs for RHEL 7 are available from the `Ansible Engine repository <https://access.redhat.com/articles/3174981>`_.
+RPMs for RHEL 7  and RHEL 8 are available from the `Ansible Engine repository <https://access.redhat.com/articles/3174981>`_.
 
-To enable the Ansible Engine repository, run the following command:
+To enable the Ansible Engine repository for RHEL 8, run the following command:
 
 .. code-block:: bash
 
-    $ sudo subscription-manager repos --enable rhel-7-server-ansible-2.7-rpms
+    $ sudo subscription-manager repos --enable rhel-8-server-ansible-2.8-rpms
+
+To enable the Ansible Engine repository for RHEL 7, run the following command:
+
+.. code-block:: bash
+
+    $ sudo subscription-manager repos --enable rhel-7-server-ansible-2.8-rpms
 
 RPMs for currently supported versions of RHEL, CentOS, and Fedora are available from `EPEL <https://fedoraproject.org/wiki/EPEL>`_ as well as `releases.ansible.com <https://releases.ansible.com/ansible/rpm>`_.