Bump django-registration-redux from 2.5 to 2.9

Bumps [django-registration-redux](https://github.com/macropin/django-registration) from 2.5 to 2.9.
- [Release notes](https://github.com/macropin/django-registration/releases)
- [Changelog](https://github.com/macropin/django-registration/blob/master/CHANGELOG)
- [Commits](macropin/django-registration@v2.5...v2.9)

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

requirements.txt

@@ -5,7 +5,7 @@ requests==2.22.0
 factory_boy==2.10.0
 coverage==4.5.1
 psycopg2==2.7.4
-django-registration-redux==2.5
+django-registration-redux==2.9
 djrill==2.1.0
 ipython==6.2.1
 boto==2.49.0