package/bison: add BISON_CPE_ID_VENDOR

cpe:2.3:a:gnu:bison is a valid CPE identifier for this package:

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

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/bison/bison.mk

@@ -9,6 +9,7 @@ BISON_SOURCE = bison-$(BISON_VERSION).tar.xz
 BISON_SITE = $(BR2_GNU_MIRROR)/bison
 BISON_LICENSE = GPL-3.0+
 BISON_LICENSE_FILES = COPYING
+BISON_CPE_ID_VENDOR = gnu
 # parallel build issue in examples/c/reccalc/
 BISON_MAKE = $(MAKE1)
 HOST_BISON_DEPENDENCIES = host-m4