Swift: Upsert data
- Primary keys must be included in 
values to use upsert. 
Examples
Upsert your data
struct Instrument: Encodable {
  let id: Int
  let name: String
}
try await supabase
  .from("instruments")
  .upsert(Instrument(id: 1, name: "piano"))
  .execute()
Bulk Upsert your data
struct Instrument: Encodable {
  let id: Int
  let name: String
}
try await supabase
  .from("instruments")
  .upsert([
    Instrument(id: 1, name: "piano"),
    Instrument(id: 2, name: "harp"),
  ])
  .execute()
Upserting into tables with constraints
struct User: Encodable {
  let id: Int
  let handle: String
  let displayName: String
  enum CodingKeys: String, CodingKey {
    case id
    case handle
    case displayName = "display_name"
  }
}
try await supabase
  .from("users")
  .upsert(
    User(id: 42, handle: "saoirse", displayName: "Saoirse"),
    onConflict: "handle"
  )
  .execute()