Update django-compressor to v2.4.0

Ghost User
2020-02-05T12:24:10+01:00

This MR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [django-compressor](https://github.com/django-compressor/django-compressor) | dependencies | minor | `~2.2` -> `~2.4` |