[AutomaticTodoList] Locations added after loading a game cause Enumerator issues

[paulwrubel]

From Nexus user PupsiMupsi:

InvalidOperationException: Collection was modified; enumeration operation may not execute.
   at System.Collections.Generic.List`1.Enumerator.MoveNext()
   at AutomaticTodoList.GameHelper.EndlessLocationsEnumerator()+MoveNext() in /home/voxaelfox/programming/stardew-mods/AutomaticTodoList/GameHelper.cs:line 34
   at AutomaticTodoList.Engines.WaterableCropsEngine.UpdateItems() in /home/voxaelfox/programming/stardew-mods/AutomaticTodoList/Engines/WaterableCropsEngine.cs:line 19
   at AutomaticTodoList.Engines.BaseEngine`1.CheckActions(Frequency frequency) in /home/voxaelfox/programming/stardew-mods/AutomaticTodoList/Engines/BaseEngine.cs:line 82
   at AutomaticTodoList.Engines.BaseEngine`1.OnUpdateTicked(UpdateTickedEventArgs e) in /home/voxaelfox/programming/stardew-mods/AutomaticTodoList/Engines/BaseEngine.cs:line 63
   at AutomaticTodoList.AutomaticTodoListManager.OnUpdateTicked(UpdateTickedEventArgs e) in /home/voxaelfox/programming/stardew-mods/AutomaticTodoList/AutomaticTodoListManager.cs:line 73
   at AutomaticTodoList.ModEntry.OnUpdateTicked(Object sender, UpdateTickedEventArgs e) in /home/voxaelfox/programming/stardew-mods/AutomaticTodoList/ModEntry.cs:line 89
   at StardewModdingAPI.Framework.Events.ManagedEvent`1.Raise(TEventArgs args) in SMAPI\Framework\Events\ManagedEvent.cs:line 101