package/mupdf: add MUPDF_CPE_ID_VENDOR

cpe:2.3:a:artifex:mupdf is a valid CPE identifier for this package:

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

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/mupdf/mupdf.mk

@@ -10,6 +10,7 @@ MUPDF_SOURCE = mupdf-$(MUPDF_VERSION)-source.tar.gz
 MUPDF_SITE = https://mupdf.com/downloads/archive
 MUPDF_LICENSE = AGPL-3.0+
 MUPDF_LICENSE_FILES = COPYING
+MUPDF_CPE_ID_VENDOR = artifex
 MUPDF_INSTALL_STAGING = YES
 MUPDF_DEPENDENCIES = \
 	freetype \