DEVELOPERS: update email address

Signed-off-by: Doug Kehn <rdkehn@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit b6c14416366d6bbd4e0664d754e8378a2cc1766b)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

DEVELOPERS

@@ -668,7 +668,7 @@ N:	Dominik Faessler <faessler@was.ch>
 F:	package/logsurfer/
 F:	package/python-id3/
 
-N:	Doug Kehn <rdkehn@yahoo.com>
+N:	Doug Kehn <rdkehn@gmail.com>
 F:	package/nss-pam-ldapd/
 F:	package/sp-oops-extract/
 F:	package/unscd/