Retain response order for Set responses #823

Lettuce now retains the response order for set results such as smembers. Previously, we used a plain HashSet that did not honor insertion order. Now we're using LinkedHashSet that retains the insertion order for unique elements.

src/main/java/com/lambdaworks/redis/output/OutputFactory.java

@@ -37,6 +37,6 @@ static <V> Set<V> newSet(int capacity) {
             return Collections.emptySet();
         }
 
-        return new HashSet<>(capacity, 1);
+        return new LinkedHashSet<>(capacity, 1);
     }
 }