Show Django's version in the django report header

[bluetech]

Fix #987.

Before:

platform linux -- Python 3.11.4, pytest-7.4.2, pluggy-1.3.0
django: settings: conf.settings (from ini)
rootdir: /my/project
configfile: pytest.ini
plugins: xdist-3.3.1, snapshot-0.9.0, django-4.5.3.dev49+g055f251

After:

platform linux -- Python 3.11.4, pytest-7.4.2, pluggy-1.3.0
django: version: 4.2.5, settings: conf.settings (from ini)
rootdir: /my/project
configfile: pytest.ini
plugins: xdist-3.3.1, snapshot-0.9.0, django-4.5.3.dev49+g055f251