Fix scores by padding and capping index to 6 digits

Author: lewispb

lib/kredis/types/unique_list.rb

@@ -46,7 +46,7 @@ def insert(elements, prepending: false)
     end
 
     def generate_score(index, negative:)
-      score = Integer([ *basis_score_components, index ].join, 10)
+      score = Integer([ *basis_score_components, index.to_s.rjust(6, "0") ].join, 10)
       negative ? -score : score
     end