package/zabbix: correct license info after 7.0.3 bump

Commit b315dc5fbf40eb0a (package/zabbix: bump version to 7.0.3) updated
zabix but forgot to check the license info, leading to legal-info failures.

Both files have changed - COPYING now specifies AGPL 3.0, so adjust hash and
license identifier.  README is now just a oneliner stating 'Please refer to
README.md' (which also does not have any license clarifications), so just
drop it.

Fixes: b315dc5fbf40eb0a (package/zabbix: bump version to 7.0.3)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/zabbix/zabbix.hash

@@ -1,4 +1,3 @@
 # Locally computed
 sha256  173059f57f11716146da79345e5a6bc52eceee6a5c4410664b8500a955598b2a  zabbix-7.0.3.tar.gz
-sha256  f8fc3fd12521b60d53d8c5d48a883eb3c9c5ddec9de986a273e1b77f69d811db  README
-sha256  444fe54aecc95ac0f3314289c300afc73b3946a4dc9fbd7e022709b3e0924dd0  COPYING
+sha256  0d96a4ff68ad6d4b6f1f30f713b18d5184912ba8dd389f86aa7710db079abcb0  COPYING

package/zabbix/zabbix.mk

@@ -8,8 +8,8 @@ ZABBIX_VERSION_MAJOR = 7.0
 ZABBIX_VERSION = $(ZABBIX_VERSION_MAJOR).3
 ZABBIX_SITE = https://cdn.zabbix.com/zabbix/sources/stable/$(ZABBIX_VERSION_MAJOR)
 ZABBIX_SELINUX_MODULES = zabbix
-ZABBIX_LICENSE = GPL-2.0+
-ZABBIX_LICENSE_FILES = README COPYING
+ZABBIX_LICENSE = AGPL-3.0
+ZABBIX_LICENSE_FILES = COPYING
 ZABBIX_CPE_ID_VENDOR = zabbix
 # We're patching m4/netsnmp.m4
 ZABBIX_AUTORECONF = YES