Automatic MTU size detection

Currently the docker compose file is creating a network with default mtu size of 1500.
Manual adding the following lines to the docker-compose.yml have the desired effect.

    driver_opts: 1442

It would by nice to have some kind of automatic detection of the mtu.
If this is too “expensive” an env key to set a value would be great as well.

Thanks anyway for a great tool!