Bump django-picklefield from 3.1 to 3.2

Bumps [django-picklefield](https://github.com/gintas/django-picklefield) from 3.1 to 3.2.
- [Commits](gintas/django-picklefield@v3.1.0...v3.2.0)

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

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

requirements/requirements.txt

@@ -91,7 +91,7 @@ django-maintenance-mode==0.21.1
     # via -r requirements/requirements.in
 django-model-utils==4.4.0
     # via -r requirements/requirements.in
-django-picklefield==3.1
+django-picklefield==3.2
     # via
     #   -r requirements/requirements.in
     #   django-constance