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>

DEVELOPERS

@@ -1050,8 +1050,10 @@ 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/