DEVELOPERS: update Sen Hastings email

phobosdpl is an old work email I don't really use anymore, so I'm
changing it to my personal email.

Signed-off-by: Sen Hastings <sen@phobosdpl.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -2765,7 +2765,7 @@ F:	package/libbson/
 F:	package/lua-resty-http/
 F:	package/mpir/
 
-N:	Sen Hastings <sen@phobosdpl.com>
+N:	Sen Hastings <sen@hastings.org>
 F:	package/systemd
 F:	support/scripts/pkg-stats