package/capnproto: add CAPNPROTO_CPE_ID_VENDOR

cpe:2.3:a:capnproto:capnproto is a valid CPE identifier for this
package:

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

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

package/capnproto/capnproto.mk

@@ -8,6 +8,7 @@ CAPNPROTO_VERSION = 0.8.0
 CAPNPROTO_SITE = $(call github,capnproto,capnproto,v$(CAPNPROTO_VERSION))
 CAPNPROTO_LICENSE = MIT
 CAPNPROTO_LICENSE_FILES = LICENSE
+CAPNPROTO_CPE_ID_VENDOR = capnproto
 CAPNPROTO_INSTALL_STAGING = YES
 # Fetched from Github with no configure script
 CAPNPROTO_AUTORECONF = YES