Edx-drf-extensions

Pick up new drf-jwt functionality to blacklist jwt tokens.

* See [CHANGELOG.rst](https://github.com/edx/edx-drf-extensions/blob/master/CHANGELOG.rst) for changes
* No longer add changes to Github Releases. Follow these instructions for [publishing a release](https://github.com/edx/edx-drf-extensions#publishing-a-release).
* For more information about why we are using CHANGELOG.rst over Github Releases, see the [Changelog ADR](https://github.com/edx/edx-drf-extensions/blob/master/docs/decisions/0001-use-changelog.rst).

With `drf-jwt>=1.15.0` unit tests running against SQLite failed to catch: the migrations of the new `blacklist` app in `drf-jwt 1.15.0` and above fail in MySQL. So downgraded the version of `drf-jwt==1.14.0`.

5.0.0 is the same release as 4.0.4. It is being released as its own major version, because 4.0.1 had **BREAKING CHANGES** and should have been its own release. This 5.0.0 version is simply being used to call additional attention to the **BREAKING CHANGES** in 4.0.1.

NOTE: At this time, we do not plan on going through the effort of releasing 4.0.5 to revert back to 4.0.0, especially because this may add confusion to those that don't expect this revert.

**WARNING**: **BREAKING CHANGES** were introduced separately in both 4.0.0 and 4.0.1.

This adds the fixes introduced in 3.0.1 to 4.x.x.