Updating the django-rate-limit requirement.
updated the django-ratelimit to use unreleased version that supports Django 2.2

Added the link to latest master commit of GitHub for Django 2.2 support.

django-appconf bump version using commit hash for django2.2

Wiki version bump.

Updating wiki.

There was a serialization issue with one of the studio JS assets that
is rendered as a part of the edit view.

- Undo the previous change.
- Pull in the version of codejail with the fix for the issue.

This reverts commit 31a3a6cb.

* Upgraded dependencies

Upgraded xblock-google-drive to latest commit hash.

- edx-sga recently released new release that supports python 3.5