swupdate: Depend on zlib

The last swupdate releases always enable CONFIG_GUNZIP which requires
zlib.

CONFIG_MTD indirectly depends on zlib and is activated in the defconfig.
However, if a defconfig without CONFIG_MTD was used, do_compile() would
fail because of the missing dependency.

Signed-off-by: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@savoirfairelinux.com>

recipes-support/swupdate/swupdate.inc

@@ -1,7 +1,7 @@
 SUMMARY="Image updater for Yocto projects"
 DESCRIPTION = "Application for automatic software update from USB Pen"
 SECTION="swupdate"
-DEPENDS += "libconfig"
+DEPENDS += "libconfig zlib"
 
 # SWUpdate licensing is described in the following pages:
 # https://sbabic.github.io/swupdate/licensing.html