package/json-for-modern-cpp: add _CPE_ID_VENDOR

cpe:2.3:a:json-for-modern-cpp_project:json-for-modern-cpp:* is a valid CPE identifier for this package:

 https://nvd.nist.gov/products/cpe/search/results?namingFormat=2.3&keyword=cpe:2.3:a:json-for-modern-cpp_project:json-for-modern-cpp

Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
[yann.morin.1998@free.fr:move up, right after license]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/json-for-modern-cpp/json-for-modern-cpp.mk

@@ -9,6 +9,8 @@ JSON_FOR_MODERN_CPP_SOURCE = json-$(JSON_FOR_MODERN_CPP_VERSION).tar.gz
 JSON_FOR_MODERN_CPP_SITE = $(call github,nlohmann,json,v$(JSON_FOR_MODERN_CPP_VERSION))
 JSON_FOR_MODERN_CPP_LICENSE = MIT
 JSON_FOR_MODERN_CPP_LICENSE_FILES = LICENSE.MIT
+JSON_FOR_MODERN_CPP_CPE_ID_VENDOR = json-for-modern-cpp_project
+
 JSON_FOR_MODERN_CPP_INSTALL_STAGING = YES
 # header only library
 JSON_FOR_MODERN_CPP_INSTALL_TARGET = NO