libcgi: add license file (with its hash)

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

package/libcgi/libcgi.hash

@@ -1,2 +1,5 @@
 # From https://github.com/rafaelsteil/libcgi/releases/download/v1.1/libcgi-1.1.tar.gz.sha256sum
 sha256  128445f2f828e84905d51bd53d11e2e08c489df3a07225ff9f198c1318092fe6  libcgi-1.1.tar.gz
+
+# Hash for license file:
+sha256  dc626520dcd53a22f727af3ee42c770e56c97a64fe3adb063799d8ab032fe551  COPYING

package/libcgi/libcgi.mk

@@ -9,5 +9,6 @@ LIBCGI_SITE = https://github.com/rafaelsteil/libcgi/releases/download/v$(LIBCGI_
 
 LIBCGI_INSTALL_STAGING = YES
 LIBCGI_LICENSE = LGPL-2.1+
+LIBCGI_LICENSE_FILES = COPYING
 
 $(eval $(cmake-package))