Fix search filters reported in #6

Author: vekien

src/XIVAPI/Api/SearchFilters.php

@@ -7,6 +7,6 @@ class SearchFilters
     const EQUAL_TO                  = '=';
     const GREATER_THAN              = '>';
     const GREATER_THAN_OR_EQUAL_TO  = '>=';
-    const LESS_THAN                 = '>';
-    const LESS_THAN_OR_EQUAL_TO     = '>=';
+    const LESS_THAN                 = '<';
+    const LESS_THAN_OR_EQUAL_TO     = '<=';
 }