Fix ordered set prepend bug (#115)

The scoring for prepended elements was not being calculated correctly.
It needs to decrement the score by 0.000001 for each element. Previously
it was increasing the score, but because the base score was decreasing
the bug was not exposed.

Using Ruby 3.2.2, performance seems to be much improved, exposing this
bug.

Author: lewispb

lib/kredis/types/ordered_set.rb

@@ -34,7 +34,13 @@ def insert(elements, prepending: false)
       return if elements.empty?
 
       elements_with_scores = types_to_strings(elements, typed).map.with_index do |element, index|
-        score = generate_base_score(negative: prepending) + (index / 100000)
+        incremental_score = index * 0.000001
+
+        score = if prepending
+          -base_score - incremental_score
+        else
+          base_score + incremental_score
+        end
 
         [ score , element ]
       end
@@ -45,10 +51,8 @@ def insert(elements, prepending: false)
       end
     end
 
-    def generate_base_score(negative:)
-      current_time = process_start_time + process_uptime
-
-      negative ? -current_time : current_time
+    def base_score
+      process_start_time + process_uptime
     end
 
     def process_start_time