~~~~~~~~~~~~~~~~~~~

- Reformatted the code using Black.
- Added equality of ``JS()`` objects to avoid adding the same script
more than once in the same configuration.
- Determine the ``static`` callable at module import time, not each time
a static path is generated.
- Customized the ``repr()`` of ``JS()`` objects.
- Added Python 3.7 and Django 2.2 to the test matrix.