package/libesmtp: set LIBESMTP_CPE_ID_VALID

cpe:2.3:a:libesmtp_project:libesmtp is a valid CPE identifier for this
package:

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

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

package/libesmtp/libesmtp.mk

@@ -12,5 +12,6 @@ LIBESMTP_CONFIG_SCRIPTS = libesmtp-config
 LIBESMTP_DEPENDENCIES = $(if $(BR2_PACKAGE_OPENSSL),openssl)
 LIBESMTP_LICENSE = GPL-2.0+ (examples), LGPL-2.1+ (library)
 LIBESMTP_LICENSE_FILES = COPYING COPYING.LIB
+LIBESMTP_CPE_ID_VALID = YES
 
 $(eval $(autotools-package))