build(deps): bump django-pydantic-field in /backend

Bumps [django-pydantic-field](https://github.com/surenkov/django-pydantic-field) from 0.3.10 to 0.3.12.
- [Release notes](https://github.com/surenkov/django-pydantic-field/releases)
- [Commits](surenkov/django-pydantic-field@v0.3.10...v0.3.12)

---
updated-dependencies:
- dependency-name: django-pydantic-field
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]