DEVELOPERS: add Giulio Benetti to all Olimex Allwinner boards' defconfigs

Add Giulio Benetti to all Olimex Allwinner boards' defconfigs since I've
recently updated and tested them all and I'd like to receive possible
build failure from gitlab CI/CD.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 1b31b4b9cef2f959915128babc5c00354f9e949f)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

DEVELOPERS

@@ -1046,8 +1046,10 @@ F:	package/webp/
 F:	package/xapian/
 
 N:	Giulio Benetti <giulio.benetti@benettiengineering.com>
+F:	board/olimex/a*
 F:	configs/amarula_vyasa_rk3288_defconfig
 F:	configs/asus_tinker_rk3288_defconfig
+F:	configs/olimex_a*
 F:	package/at/
 F:	package/binutils/
 F:	package/erlang-jiffy/