Update to modern python 3/django 3/recaptcha v3

[9mido]

This package has not seen an update in a while. Update it to work with the latest python and django versions.

[axil]

@9mido There is life in @mmangione's fork: https://github.com/mmangione/django-captcha-admin but it not perfect either: my PR (mmangione#1) upgrades this to recaptcha v3 and django2.2.12.

[9mido]

@axil Awesome thank you for your efforts on this hopefully it can be completed soon.

[axil]

Not really sure what you mean by completed. Actually you can clone https://github.com/axil/django-captcha-admin and work right now. I haven't tested it with django 3 though.

[9mido]

@axil Oh when I mentioned completed I thought you were trying to make it perfect since you said it was not. Ah gotcha thank you for that I will check it out.