firewall4: add missing PKG_MIRROR_HASH

Fixes: 84183f0d98 ("firewall4: update to latest Git HEAD")
Signed-off-by: Jo-Philipp Wich <[email protected]>

package/network/config/firewall4/Makefile

@@ -11,7 +11,7 @@ PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/firewall4.git
 PKG_SOURCE_DATE:=2022-11-29
 PKG_SOURCE_VERSION:=700a925fd9c1f1ff404e6b125cd5347ad7c45668
-PKG_MIRROR_HASH:=
+PKG_MIRROR_HASH:=18fb7a27399bf2e9e094a4cbacd4e859448c1c9194b6da4a78c9f37a642d1703
 PKG_MAINTAINER:=Jo-Philipp Wich <[email protected]>
 PKG_LICENSE:=ISC