MAINTAINERS: Remove non-working address from MAINTAINERS

MAINTAINERS: Remove non-working address from MAINTAINERS

The address ariel.dalessandro@collabora.com is no longer working:

  A message that you sent could not be delivered to one or more of its
  recipients. This is a permanent error. The following address(es) failed:

  ariel.dalessandro@collabora.com
    host mx.collabora.co.uk [46.235.227.165]
    SMTP error from remote mail server after RCPT TO:<ariel.dalessandro@collabora.com>:
    550 5.1.1 <ariel.dalessandro@collabora.com>: Recipient address rejected:
    undeliverable address: host mail.collabora.co.uk[46.235.227.172] said:
    550 5.1.1 <ariel.dalessandro@collabora.com>: Recipient address rejected:
    User unknown in local recipient table (in reply to RCPT TO command)

Remove this address from MAINTAINERS.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>