Wrong list indention in supported options for EmailAddress validator

[froschdesign]

The documentation is build with MkDocs and this uses Python-Markdown:

a list item must be indented by either 4 spaces

https://python-markdown.github.io/#differences

Compare:

• https://github.com/zendframework/zend-validator/blob/master/doc/book/validators/email-address.md#supported-options
• https://docs.zendframework.com/zend-validator/validators/email-address/#supported-options