package/paho-mqtt-c: bump to version 1.3.7

Paho-mqtt-c maintainance release. It fixes some bugs including client
times out and buffer overflow:

https://github.com/eclipse/paho.mqtt.c/milestone/9?closed=1

Signed-off-by: Julien Grossholtz <julien.grossholtz@openest.io>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

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

@@ -1,5 +1,5 @@
 # Locally computed:
-sha256  ecbc2c2000c6d8dcf1a76325312c61ed29db0b010acbd40cb92fcd4c014cd017  paho-mqtt-c-1.3.6.tar.gz
+sha256  19e9f04ddf244ab8c937d7e631ca15cedce7df95712c554107600e80efdaf277  paho-mqtt-c-1.3.7.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 = 1.3.6
+PAHO_MQTT_C_VERSION = 1.3.7
 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