Fix trimming of adressess with array_map (#32)

[array_map)(https://www.php.net/manual/en/function.array-map.php) returns new array as result, it does not work on the passed array in-place. This is true for PHP versions back to 4.3.0 (https://3v4l.org/FkJHL), the lowest available version on 3v4l.org.

This was first introduced in 4bab560 and probably never worked since then.

Mail/RFC822.php

@@ -486,7 +486,7 @@ protected function _validateAddress($address)
  }
 
  // Trim the whitespace from all of the address strings.
- array_map('trim', $addresses);
+ $addresses = array_map('trim', $addresses);
 
  // Validate each mailbox.
  // Format could be one of: name <geezer@domain.com>