CRM-20270 - composer.lock - Fix multibyte warnings by updating ezcMail

CRM-20270 - composer.lock - Fix multibyte warnings by updating ezcMail

On many systems, the test suite outputs a long message which begins with:

```
PHP Warning: declare(encoding=...) ignored because Zend multibyte feature is turned off by settings in /path/to/sites/all/modules/civicrm/vendor/zetacomponents/mail/src/transports/variable/var_set.php on line 2
```

This patch addresses the warning by updating the version of ezcMail (aka `zetacomponents/mail`).  See also:

 * https://github.com/civicrm/zetacomponents-mail/pull/1
 * http://civicrm.stackexchange.com/questions/16314/does-civicrm-have-a-recommended-setting-for-zend-multibyte