DEVELOPERS: remove Roman Gorbenkov, e-mail bouncing

<roman.gorbenkov@ens2m.org>: host mxd.relay.renater.fr[194.214.200.9] said: 550
    5.5.0 Requested actions not taken as the mailbox is unavailable (in reply
    to RCPT TO command)

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>