Bump django-select2 from 8.3.0 to 8.4.0

Bumps [django-select2](https://github.com/codingjoe/django-select2) from 8.3.0 to 8.4.0.
- [Release notes](https://github.com/codingjoe/django-select2/releases)
- [Commits](codingjoe/django-select2@8.3.0...8.4.0)

---
updated-dependencies:
- dependency-name: django-select2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]