package/paho-mqtt-c: security bump to version 1.3.12

Contains a fix for a possible race condition that can lead to use after
free:
https://github.com/eclipse/paho.mqtt.c/commit/911488a9f0fdad31c85ec86712be52587afdbbb8

https://github.com/eclipse/paho.mqtt.c/milestone/19?closed=1

https://github.com/eclipse/paho.mqtt.c/releases/tag/v1.3.12

Signed-off-by: Daniel Lang <d.lang@abatec.at>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/paho-mqtt-c/paho-mqtt-c.hash

@@ -1,5 +1,5 @@
 # Locally computed:
-sha256  d7bba3f8b8978802e11e2b1f28e96e6b7f4ed5d8a268af52a4d3b1bcbd1db16b  paho-mqtt-c-1.3.11.tar.gz
+sha256  6a70a664ed3bbcc1eafdc45a5dc11f3ad70c9bac12a54c2f8cef15c0e7d0a93b  paho-mqtt-c-1.3.12.tar.gz
 sha256  83bbba033dc985487e321b6dfde111772affb73460be48726299fed3da684b1c  edl-v10
 sha256  0becf16567beb77fa252b7664631dd177c8f9a1889e48995b45379c7130e5303  epl-v20
 sha256  bc0f3f447097eb82a29ad6c2f4929572bb548b6bd4c9e38fde1bf131a771b7a0  LICENSE

package/paho-mqtt-c/paho-mqtt-c.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-PAHO_MQTT_C_VERSION = 1.3.11
+PAHO_MQTT_C_VERSION = 1.3.12
 PAHO_MQTT_C_SITE = $(call github,eclipse,paho.mqtt.c,v$(PAHO_MQTT_C_VERSION))
 PAHO_MQTT_C_LICENSE = EPL-2.0 or BSD-3-Clause
 PAHO_MQTT_C_LICENSE_FILES = epl-v20 edl-v10 LICENSE