Webapp User Model is missing "scmUri" property

https://github.com/Azure/azure-rest-api-specs/blob/current/specification/web/resource-manager/Microsoft.Web/2016-08-01/WebApps.json#L20960

I need to access the `properties/scmUri` field, which is missing from the swagger spec. Please add this.

ex:
```
{
"id": "/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590/resourceGroups/wilx-group/providers/Microsoft.Web/sites/rubyhello/publishingcredentials/$rubyhello",
"name": "rubyhello",
"type": "Microsoft.Web/sites/publishingcredentials",
"location": "East US",
"properties": {
"name": null,
"publishingUserName": "$rubyhello",
"publishingPassword": ,
"publishingPasswordHash": null,
"publishingPasswordHashSalt": null,
"metadata": null,
"isDeleted": false,
"scmUri": "https://$rubyhello:Goosgxcazi4pduzwnYyXatPpa4wQ7gSpnlR8ml6vvN8J6RKPwTrj2WfZKg2Z@rubyhello.scm.azurewebsites.net"
}
}
```