Enum UpgradeTargets added

Assets/Scripts/UpgradeTargets.cs

+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public enum UpgradeTargets
+    {population, capacity, speed, collector}
+

Assets/Scripts/UpgradeTargets.cs.meta

+fileFormatVersion: 2
+guid: 52b1be7ed8d1a644297ee36070df4ab2
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: