Update workout

PUT http://localhost:3000/api/v1/workouts/6

{
  "location_id": 3,
  "title": "38 Sections for Time",
  "date": "2004-10-19 10:23:54+02",
  "lat": 42.366032,
  "lng": -71.127376,
  "type_id": 5
}