Bump django-tinymce from 2.9.0 to 3.4.0 in /src/requirements

Bumps [django-tinymce](https://github.com/jazzband/django-tinymce) from 2.9.0 to 3.4.0.
- [Release notes](https://github.com/jazzband/django-tinymce/releases)
- [Changelog](https://github.com/jazzband/django-tinymce/blob/master/CHANGELOG.rst)
- [Commits](jazzband/django-tinymce@2.9.0...3.4.0)

---
updated-dependencies:
- dependency-name: django-tinymce
  dependency-type: direct:production
...

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

Author: dependabot[bot]

src/requirements/base.in

@@ -60,7 +60,7 @@ django-staff-toolbar == 2.0
 django-tag-parser == 3.2
 django-taggit == 2.1.0
 django-threadedcomments == 2.0
-django-tinymce == 2.9.0
+django-tinymce == 3.4.0
 django-webmaster-verification == 0.3.0
 django-wysiwyg == 0.8.0
 docutils == 0.18.1