Update default maxWireVersion

[ShaneHarvey]

The current default maxWireVersion is 6 which represents the now EOL MongoDB 3.6. We should update the default to 25 which represents MongoDB 8.0.

[ShaneHarvey]

We could also use MAX_SUPPORTED_WIRE_VERSION or MIN_SUPPORTED_WIRE_VERSION from pymongo.common instead of hardcoding it.

[ShaneHarvey]

Note this is motivated by mongodb/mongo-python-driver#1905 because PyMongo is dropping support for MongoDB 3.6. We should implement and release this ticket before releasing the next version of pymongo otherwise pymongo won't be able to connect to MockupDB by default.