package/python-django: security bump to version 3.0.4

Fixes the following security vulnerabilities:

- CVE-2020-9402: Potential SQL injection via tolerance parameter in GIS
  functions and aggregates on Oracle.
  GIS functions and aggregates on Oracle were subject to SQL injection,
  using a suitably crafted tolerance.

For more details, see the advisory:
https://www.djangoproject.com/weblog/2020/mar/04/security-releases/



Signed-off-by: Peter Korsgaard <peter@korsgaard.com>