yggdrasil: package LICENSE filename, update license id name

Signed-off-by: William Fleurant <meshnet@protonmail.com>

net/yggdrasil/Makefile

@@ -10,7 +10,8 @@ PKG_HASH:=dc1699064319f19a64ac57bac366a15d718008fdb75ef03bf4252d3552dff4eb
 PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_NAME)-go-$(PKG_VERSION)
 
 PKG_MAINTAINER:=William Fleurant <meshnet@protonmail.com>
-PKG_LICENSE:=GPL-3.0-or-later
+PKG_LICENSE:=LGPL-3.0-only
+PKG_LICENSE_FILES:=LICENSE
 
 PKG_BUILD_DEPENDS:=golang/host
 PKG_BUILD_PARALLEL:=1