Pin Django Rest Framework version to branch with fixes to https://github.com/encode/django-rest-framework/issues/3354.
Pin Django Rest Framework version
to branch with fixes to https://github.com/encode/django-rest-framework/issues/3354.

Signed-off-by: Tomasz Gargas <dd7daed03936e0c371e2c3aa653cd5b196895201@opencraft.com>

edx-solutions/edx-platform,edx-solutions/edx-platform,edx-solutions/edx-platform,edx-solutions/edx-platform