Typo in the System Requirements page of Horizon

[Ramdass]

The word previous wrongly typed as 'prevouos'

Please refer the below,

- [x] This doc is inaccurate in this way:
     The prevouos LTS of Django 1.11 will be dropped during Ussuri cycle. Django 2.0 support will be dropped as well.

- [x] I have a fix to the document that I can paste below including example:

   The previous LTS of Django 1.11 will be dropped during Ussuri cycle. Django 2.0 support will be dropped as well.

-----------------------------------
Release: 18.6.2.dev3 on 2020-08-20 07:14:53
SHA: 969c7e930f00601b888a646e6441a0c5785ff4e7
Source: https://opendev.org/openstack/horizon/src/doc/source/install/system-requirements.rst
URL: https://docs.openstack.org/horizon/victoria/install/system-requirements.html

[Akihiro Motoki (amotoki)]

https://review.opendev.org/c/openstack/horizon/+/763978 will fix the issue indirectly.
The content which includes the reported type is no longer needed.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/horizon 19.0.0 release.