api: swagger: add IPAMConfig on IPAM

Signed-off-by: Niel Drummond <niel@drummond.lu>

api/swagger.yaml

@@ -2035,15 +2035,27 @@ definitions:
           ```
         type: "array"
         items:
-          type: "object"
-          additionalProperties:
-            type: "string"
+          $ref: "#/definitions/IPAMConfig"
       Options:
         description: "Driver-specific options, specified as a map."
         type: "object"
         additionalProperties:
           type: "string"
 
+  IPAMConfig:
+    type: "object"
+    properties:
+      Subnet:
+        type: "string"
+      IPRange:
+        type: "string"
+      Gateway:
+        type: "string"
+      AuxiliaryAddresses:
+        type: "object"
+        additionalProperties:
+          type: "string"
+
   NetworkContainer:
     type: "object"
     properties: