Apply "random_api_migration" CS rule

Author: phansys

.php-cs-fixer.dist.php

@@ -28,6 +28,7 @@
         'php_unit_set_up_tear_down_visibility' => true,
         'php_unit_test_annotation' => false,
         'php_unit_test_case_static_method_calls' => true,
+        'random_api_migration' => true,
         'static_lambda' => true,
         'ternary_to_null_coalescing' => true,
     ])

tests/Gedmo/Tree/Fixture/User.php

@@ -67,7 +67,7 @@ public function generateString($length = 8)
         $num = strlen($set);
         $ret = '';
         for ($i = 0; $i < $length; ++$i) {
-            $ret .= $set[rand(0, $num - 1)];
+            $ret .= $set[mt_rand(0, $num - 1)];
         }
 
         return $ret;