new: Allow defining interfaces on Instance creation - #372

from linode_api4 import LinodeClient
from linode_api4.objects import ConfigInterface

    client = LinodeClient(os.getenv("LINODE_TOKEN"))
    
    linode_instance, password = client.linode.instance_create(
        "g6-nanode-1",
        "us-east",
        label="test-instance",
        image="linode/debian10",
        interfaces=[
            {"purpose": "public"},
            ConfigInterface(
                purpose="vlan", label="cool-vlan", ipam_address="10.0.0.4/32"
            ),
        ],
    )
    
    print(linode_instance.configs[0].interfaces[0].purpose)