Change upload creation example app method to use discardableResult (#34)

Author: andrewjl-mux

Example/SwiftUploadSDKExample/SwiftUploadSDKExample/Model/UploadCreationModel.swift

@@ -41,7 +41,7 @@ class UploadCreationModel : ObservableObject {
         }
     }
 
-    func startUpload(preparedMedia: PreparedUpload, forceRestart: Bool) -> MuxUpload {
+    @discardableResult func startUpload(preparedMedia: PreparedUpload, forceRestart: Bool) -> MuxUpload {
         let upload = MuxUpload(
             uploadURL: preparedMedia.remoteURL,
             videoFileURL: preparedMedia.localVideoFile

Example/SwiftUploadSDKExample/SwiftUploadSDKExample/Screens/CreateUploadView.swift

@@ -148,7 +148,7 @@ fileprivate struct ThumbnailView: View {
             Spacer()
             StretchyDefaultButton("Upload") {
                 if let preparedMedia = preparedMedia {
-                    let upload = uploadCreationVM.startUpload(preparedMedia: preparedMedia, forceRestart: true)
+                    uploadCreationVM.startUpload(preparedMedia: preparedMedia, forceRestart: true)
                     dismiss()
                 }
             }