fix generator skipping item drop

[dhiepp]

Identify the Bug

Iron and Gold generators don't drop the correct amount of items
For example if you set in config amount: 3 then it will only drop 2 items
and if you set in config amount: 5 then it will only drop 3 items

This bug is caused by an extra line in OreGenerator class dropItem method
temp--;
We don't need that extra line because the loop's logic is flawed:
temp = amount as the starting statement will set temp variable to the amount we want
temp >= 0 as the ending condition will make it spawn an extra item because when temp variable is at zero, the loop still continues one more time

Description of the Change

Set the loop's ending condition to temp > 0 will make the loop stop when the correct amount of items have been spawned, so we don't need that extra line anymore

[andrei1058]

Thank you!