DEVELOPERS: add skarnet.org packages to J. Neuschäfer's entry

Since I've contributed some maintenance to s6 and other packages from
skarnet.org in the past, I'm stepping up to be notified of developments
in these packages.

Signed-off-by: J. Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -1453,7 +1453,16 @@ F:	package/axel/
 F:	package/mawk/
 
 N:	J. Neuschäfer <j.neuschaefer@gmx.net>
-F:	package/tipidee
+F:	package/execline/
+F:	package/mdevd/
+F:	package/s6/
+F:	package/s6-linux-init/
+F:	package/s6-linux-utils/
+F:	package/s6-networking/
+F:	package/s6-portable-utils/
+F:	package/s6-rc/
+F:	package/skalibs/
+F:	package/tipidee/
 
 N:	Jagan Teki <jagan@amarulasolutions.com>
 F:	board/amarula/