Fix distributedcloud-client openstack-tox-docs

[Victor Romano]

Brief Description
-----------------
The openstack-tox-docs fails with: Invalid configuration value found: 'language = None'. Update your configuration to a valid language code. Falling back to 'en' (English).

Severity
--------
<Critical: System/Feature is not usable due to the defect>

Steps to Reproduce
------------------
Commit a change

Expected Behavior
------------------
All zuul jobs pass.

Actual Behavior
----------------
openstack-tox-docs failed.

Reproducibility
---------------
<Reproducible>

System Configuration
--------------------
<One node system, Two node system, Multi-node system, Dedicated storage, https, IPv4, IPv6 etc.>

Branch/Pull Time/Commit
-----------------------
master

Last Pass
---------
NA

Timestamp/Logs
--------------
NA

Test Activity
-------------
NA

Workaround
----------
NA

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/distcloud-client/+/893226

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/distcloud-client/+/893226
Committed: https://opendev.org/starlingx/distcloud-client/commit/eee5c7cedfc16e10ff6f32e7bab1ab1c650e06a4
Submitter: "Zuul (22348)"
Branch: master

commit eee5c7cedfc16e10ff6f32e7bab1ab1c650e06a4
Author: Victor Romano <email address hidden>
Date: Wed Aug 30 13:36:25 2023 -0300

    Fix distributedcloud-client openstack-tox-docs

    This change the default docs language conf to 'en'
    instead of None.

    Closes-Bug: 2033542

    Change-Id: I8a6a5656f9e6993609a43a521547e3d84fd09c77
    Signed-off-by: Victor Romano <email address hidden>