Handle networks.driver_opts for a service

These are endpoint-specific driver options...

services:
  myservice:
    image: myimage
    networks:
      mynet:
        driver_opts:
          "option1": "value1"

The API has had support for a long time, it's only recently been
added to compose (unreleased right now).

Signed-off-by: Rob Murray <rob.murray@docker.com>

cli/compose/schema/data/config_schema_v3.13.json

@@ -197,6 +197,12 @@
                       "type": "object",
                       "properties": {
                         "aliases": {"$ref": "#/definitions/list_of_strings"},
+                        "driver_opts": {
+                          "type": "object",
+                          "patternProperties": {
+                            "^.+$": { "type": ["string", "number"] }
+                          }
+                        },
                         "ipv4_address": {"type": "string"},
                         "ipv6_address": {"type": "string"}
                       },