Support for Connection.create_function

[Peter Baumgartner]

Hitting this in https://github.com/lincolnloop/django-libsql

It stems from https://github.com/django/django/blob/4.2/django/db/backends/sqlite3/_functions.py#L41

The relevant part of the traceback is:

  File "/Users/pete/projects/lincolnloop/django-libsql/src/django_libsql/base.py", line 29, in get_new_connection
    register_functions(conn)
  File "/Users/pete/projects/lincolnloop/django-libsql/django/django/db/backends/sqlite3/_functions.py", line 42, in register
    connection.create_function,
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'builtins.Connection' object has no attribute 'create_function'