Bump django-debug-toolbar from 1.2.2 to 1.11.1 in /requirements

Bumps [django-debug-toolbar](https://github.com/jazzband/django-debug-toolbar) from 1.2.2 to 1.11.1.
- [Release notes](https://github.com/jazzband/django-debug-toolbar/releases)
- [Changelog](https://github.com/jazzband/django-debug-toolbar/blob/1.11.1/docs/changes.rst)
- [Commits](https://github.com/jazzband/django-debug-toolbar/compare/1.2.2...1.11.1)

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

requirements/dev-requirements.txt

@@ -1,5 +1,5 @@
 -r test-requirements.txt
-django-debug-toolbar==1.2.2
+django-debug-toolbar==1.11.1
 ipdb==0.8
 ipython==2.3.1
 pygraphviz==1.2