Description of problem:
liblognorm fails to build documentation with Sphinx 5 in Fedora Rawhide as it sets language to None instead of a valid language string in its conf.py (eg. 'en'). 
Sphinx 5+ doesn't accept such setting.


Version-Release number of selected component (if applicable):
2.0.6-3

How reproducible:
Always

Steps to Reproduce:
$ mock -r fedora-rawhide-x86_64 --addrepo=https://download.copr.fedorainfracloud.org/results/ksurma/sphinx-5/fedora-rawhide-x86_64/ --no-clean <your.src.rpm>
$ mock -r fedora-rawhide-x86_64 --addrepo=https://download.copr.fedorainfracloud.org/results/ksurma/sphinx-5/fedora-rawhide-x86_64/ shell


Actual results:
sphinx-build -b html -d _build/doctrees -n -W -c . . _build/html
Running Sphinx v5.0.2

Warning, treated as error:
Invalid configuration value found: 'language = None'. Update your configuration to a valid langauge code. Falling back to 'en' (English).

Expected results:
Build succeeds