package/libcpprestsdk: put back zlib dependency

zlib dependency was wrongly removed by commit
3037e99ae67f159626c0b148da46008e1dd23e91

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

package/libcpprestsdk/libcpprestsdk.mk

@@ -10,7 +10,7 @@ LIBCPPRESTSDK_LICENSE = MIT
 LIBCPPRESTSDK_LICENSE_FILES = license.txt
 LIBCPPRESTSDK_SUBDIR = Release
 LIBCPPRESTSDK_INSTALL_STAGING = YES
-LIBCPPRESTSDK_DEPENDENCIES += host-pkgconf boost openssl
+LIBCPPRESTSDK_DEPENDENCIES += host-pkgconf boost openssl zlib
 LIBCPPRESTSDK_CONF_OPTS = -DWERROR=OFF -DBUILD_SAMPLES=OFF
 
 ifeq ($(BR2_STATIC_LIBS),y)