package/unbound: install to staging

Needed for Monero:
https://github.com/monero-project/monero/blob/release-v0.18/cmake/FindUnbound.cmake

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/unbound/unbound.mk

@@ -6,6 +6,7 @@
 
 UNBOUND_VERSION = 1.17.0
 UNBOUND_SITE = https://www.unbound.net/downloads
+UNBOUND_INSTALL_STAGING = YES
 UNBOUND_DEPENDENCIES = host-pkgconf expat libevent openssl
 UNBOUND_LICENSE = BSD-3-Clause
 UNBOUND_LICENSE_FILES = LICENSE