Bump django-reversion from 5.0.1 to 5.1.0

Bumps [django-reversion](https:/etianen/django-reversion) from 5.0.1 to 5.1.0.
- [Release notes](https:/etianen/django-reversion/releases)
- [Changelog](https:/etianen/django-reversion/blob/master/CHANGELOG.rst)
- [Commits](etianen/django-reversion@v5.0.1...v5.1.0)

---
updated-dependencies:
- dependency-name: django-reversion
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -107,7 +107,7 @@ requirements/src/django_audit_log-0.8.2-py2.py3-none-any.whl
 djangorestframework==3.14.0
 djangorestframework-jsonp==1.0.2
 Unidecode==1.3.2
-django-reversion==5.0.1
+django-reversion==5.1.0
 python-dateutil==2.9.0
 requirements/src/edtf-0.9.3ctl-py2.py3-none-any.whl