Bump version number

Add tag 2.4.0.

Merge pull request #33 from FlipperPA/feature/2.3-release

Release branch for 2.3 release with support for Click 8.

Switch to 88 chars to be compliant with Black.

Bump version to 2.1.1.

django-click release version 2.1.0

django-click release version 2.0.0

django-click release version 1.2.0

django-click release version 1.0.0

django-click release version 0.1.1