Remove unused imports from DeptHighestAvgSalaryQ20 class

Author: kumarcodes

src/main/java/com/superthirty/DeptHighestAvgSalaryQ20.java

@@ -1,7 +1,5 @@
 package com.superthirty;
 
-import java.util.Collections;
-import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;