Tomás Agustín González Orlando authored Dec 12, 2022 and Diego Sueiro committed Dec 12, 2022

The README.md contains information on how to build the documentation locally.
Change the version of Ubuntu at which this build has been tested to a more
updated one and to be consistent with the rest of the documentation.

Issue-Id: SCM-5314
Signed-off-by: Tomás González <tomasagustin.gonzalezorlando@arm.com>
Change-Id: I0d5a4d02a0ddccb9ba7dbe366448e7fbc58ae1f7