Add support for Django 3.2 - 5.0 and Python 3.10 - 3.12

[browniebroke]

Update official support matrix for Django and Python versions to match upstream support.

FWIW, we already use this package with Python 3.11 and Django 4.2 (soon 3.12 & 5.0), but I thought it was worth updating official support on CI.

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