DEVELOPERS: update email address

This patch updates my email address in the DEVELOPERS file.

Signed-off-by: Christian Stewart <christian@aperture.us>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit e538824692822cab06c44e6b70e9ae3b92d4c920)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

DEVELOPERS

@@ -516,7 +516,7 @@ F:	package/syslog-ng/
 N:	Christian Kellermann <christian.kellermann@solectrix.de>
 F:	package/python-pylibftdi/
 
-N:	Christian Stewart <christian@paral.in>
+N:	Christian Stewart <christian@aperture.us>
 F:	package/balena-engine/
 F:	package/batman-adv/
 F:	package/containerd/