package/libvncserver: fix homepage

libvncserver homepage is https://libvnc.github.io/, last version on
sourceforge is 0.9.9 (seven years ago)

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

package/libvncserver/Config.in

@@ -6,7 +6,7 @@ config BR2_PACKAGE_LIBVNCSERVER
 	help
 	  libvncserver is a VNC server/client library.
 
-	  http://libvncserver.sourceforge.net/
+	  https://libvnc.github.io/
 
 if BR2_PACKAGE_LIBVNCSERVER