Race condition in orleans/ShoppingCart/Grains/InventoryGrain.cs#L48

[TimonPasslick]

A parallel for loop writes to a dictionary without mutual exclusion: https://github.com/dotnet/samples/blob/main/orleans/ShoppingCart/Grains/InventoryGrain.cs#L48

[TimonPasslick]

I will fix this myself, it's just a small change.