package/mono: add MONO_CPE_ID_VENDOR

cpe:2.3:a:mono-project:mono is a valid CPE identifier for this package:

  https://nvd.nist.gov/products/cpe/search/results?namingFormat=2.3&keyword=cpe%3A2.3%3Aa%3Amono-project%3Amono

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/mono/mono.mk

@@ -10,6 +10,7 @@ MONO_SOURCE = mono-$(MONO_VERSION).tar.xz
 MONO_LICENSE = GPL-2.0 or MIT (compiler, tools), MIT (libs) or commercial
 MONO_LICENSE_FILES = LICENSE mcs/COPYING \
 	external/Newtonsoft.Json/Tools/7-zip/copying.txt
+MONO_CPE_ID_VENDOR = mono-project
 MONO_INSTALL_STAGING = YES
 
 ## Mono native