libcoap: update to 4.2.1

Signed-off-by: Rosen Penev <rosenp@gmail.com>

libs/libcoap/Makefile

@@ -8,12 +8,12 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libcoap
-PKG_VERSION:=4.2.0
-PKG_RELEASE:=2
+PKG_VERSION:=4.2.1
+PKG_RELEASE:=1
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://codeload.github.com/obgm/libcoap/tar.gz/v$(PKG_VERSION)?
-PKG_HASH:=9523e38da6ee8b2a8f5ce83ded64107dd1e514c7ad00cd74ccfe3454b679c271
+PKG_HASH:=29a0394a265d3febee41e5e2dc03d34292a0aede37f5f80334e529ac0dab2321
 
 PKG_MAINTAINER:=Anton Glukhov <anton.a.glukhov@gmail.com>
 PKG_LICENSE:=GPL-2.0-or-later BSD-2-Clause