remove useless Builder from day 20

Author: ythirion

solution/day20/src/test/java/constrain/input/DiceBuilder.java

@@ -1,5 +1,6 @@
 package constrain.input;
 
+import builders.DiceBuilder;
 import domain.yahtzee.constrain.input.Error;
 import domain.yahtzee.constrain.input.Roll;
 import domain.yahtzee.constrain.input.YahtzeeCalculator;