libubox: update to version 2019-12-28

Fixes startup issues of some services in procd and bumps ABI_VERSION to 20191228.

Ref: http://lists.infradead.org/pipermail/openwrt-devel/2019-December/020840.html
Signed-off-by: Petr Štetiar <ynezz@true.cz>

package/libs/libubox/Makefile

@@ -5,9 +5,9 @@ PKG_RELEASE=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/libubox.git
-PKG_MIRROR_HASH:=8072cf0ca0b4de23ad91bffae95a1e3a243ca2e4736e114992d5a7ebc2185235
-PKG_SOURCE_DATE:=2019-12-26
-PKG_SOURCE_VERSION:=eb7eb6393d47a918c420f5b287946dbd6c0d5f57
+PKG_MIRROR_HASH:=90511058f49a178a816d520944cddba421f9eb50c319ef1623bed7aa22f94a3a
+PKG_SOURCE_DATE:=2019-12-28
+PKG_SOURCE_VERSION:=cd75136b1342e1e9dabf921be13240c6653640ed
 CMAKE_INSTALL:=1
 
 PKG_LICENSE:=ISC
@@ -27,7 +27,7 @@ define Package/libubox
   SECTION:=libs
   CATEGORY:=Libraries
   TITLE:=Basic utility library
-  ABI_VERSION:=20191226
+  ABI_VERSION:=20191228
   DEPENDS:=
 endef