change default criteria encode mode

* this change does not appear to break any existing tests
* this change fixes #250

Author: bapcltd-marv

src/PhpImap/Imap.php

@@ -814,7 +814,7 @@ public static function search(
         string $criteria,
         int $options = SE_FREE,
         string $charset = null,
-        bool $encodeCriteriaAsUtf7Imap = true
+        bool $encodeCriteriaAsUtf7Imap = false
     ): array {
         \imap_errors(); // flush errors