Bump django from 1.10.6 to 1.11.29

Bumps [django](https://github.com/django/django) from 1.10.6 to 1.11.29.
- [Release notes](https://github.com/django/django/releases)
- [Commits](https://github.com/django/django/compare/1.10.6...1.11.29

)

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

requirements.txt

-django==1.10.6
+django==1.11.29
 Markdown==2.6.8
 Pygments==2.2.0
 pytz==2016.10