Support psycopg3

[janrito]

Probably not one for this PR but we should also consider supporting psycopg3, especially with Django 4.2+ supporting it. I think Django's done a pretty good job abstracting away differences, so support would hopefully only be a problem if we use private Django internals. You can have a look for is_psycopg3 in Django >=4.2 source code for where the the differences are under the hood

• https://www.psycopg.org/psycopg3/docs/basic/from_pg2.html

Originally posted by @kevinmarsh in #1 (comment)