Fix typos discovered by codespell

[cclauss]

Fix typos discovered by codespell - https://pypi.org/project/codespell

% codespell

./CHANGELOG.md:25: tha ==> than, that, the
./CHANGELOG.md:52: ot ==> to, of, or, not, it
./update_version_from_git.py:100: verion ==> version
./django_prometheus/exports.py:24: listenning ==> listening

% codespell --write-changes