Only use postgres CursorDebugWrapper with Django 3

debug_toolbar/management/commands/debugsqlshell.py

@@ -1,10 +1,11 @@
 from time import time
 
+import django
 import sqlparse
 from django.core.management.commands.shell import Command  # noqa
 from django.db import connection
 
-if connection.vendor == "postgresql":
+if connection.vendor == "postgresql" and django.VERSION >= (3, 0, 0):
     from django.db.backends.postgresql import base as base_module
 else:
     from django.db.backends import utils as base_module

tests/commands/test_debugsqlshell.py

@@ -1,13 +1,14 @@
 import io
 import sys
 
+import django
 from django.contrib.auth.models import User
 from django.core import management
 from django.db import connection
 from django.test import TestCase
 from django.test.utils import override_settings
 
-if connection.vendor == "postgresql":
+if connection.vendor == "postgresql" and django.VERSION >= (3, 0, 0):
     from django.db.backends.postgresql import base as base_module
 else:
     from django.db.backends import utils as base_module