Bump django-pipeline from 2.1.0 to 3.1.0

Bumps [django-pipeline](https://github.com/jazzband/django-pipeline) from 2.1.0 to 3.1.0.
- [Release notes](https://github.com/jazzband/django-pipeline/releases)
- [Changelog](https://github.com/jazzband/django-pipeline/blob/master/HISTORY.rst)
- [Commits](jazzband/django-pipeline@2.1.0...3.1.0)

---
updated-dependencies:
- dependency-name: django-pipeline
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements/base.txt

@@ -30,7 +30,7 @@ uk-election-ids==0.7.5
 uk-election-timetables==2.4.1
 uk-geo-utils==0.12.0
 
-django-pipeline==3.0.0
+django-pipeline==3.1.0
 
 importlib-metadata==6.8.0