Staff-graded-xblock

What's Changed
* Standardize version number placement by aht007 in https://github.com/openedx/staff_graded-xblock/pull/77
* Post Django32 cleanup by aht007 in https://github.com/openedx/staff_graded-xblock/pull/87

New Contributors
* aht007 made their first contribution in https://github.com/openedx/staff_graded-xblock/pull/77

**Full Changelog**: https://github.com/openedx/staff_graded-xblock/compare/1.6.0...2.0.0

Added support for following Django versions in PR [67 ](https://github.com/edx/staff_graded-xblock/pull/67):
- 3.0
- 3.1
- 3.2

Fixes broken import

Python requirements update

Fix instance of `DeprecatedEdxPlatformImportWarning` in preparation for removal of deprecated import support.