package/rust: add CPE_ID_VENDOR

This gives a proper cpe-id string to the Rust buildroot package,
as it can be found in the NVD database:
https://nvd.nist.gov/products/cpe/search/results?keyword=cpe:2.3:a:rust-lang:rust

Signed-off-by: Titouan Christophe <titouan.christophe@mind.be>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/rust/rust.mk

@@ -11,6 +11,7 @@ RUST_SOURCE = rustc-$(RUST_VERSION)-src.tar.xz
 RUST_SITE = https://static.rust-lang.org/dist
 RUST_LICENSE = Apache-2.0 or MIT
 RUST_LICENSE_FILES = LICENSE-APACHE LICENSE-MIT
+RUST_CPE_ID_VENDOR = rust-lang
 
 HOST_RUST_PROVIDES = host-rustc