package/open62541: bump to version 1.3.15

For release notes since 1.3.12, see:
https://github.com/open62541/open62541/releases/tag/v1.3.15
https://github.com/open62541/open62541/releases/tag/v1.3.14
https://github.com/open62541/open62541/releases/tag/v1.3.13

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
[Julien: add link to release notes]
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/open62541/open62541.hash

@@ -1,3 +1,3 @@
 # Locally calculated
-sha256  dab44ad50b10cc5f9e9e1f44f0510e0c5f7a8226c6bba821babafc5a79acdc2d  open62541-v1.3.12-git4.tar.gz
+sha256  a8719f299505b144bd68bf557ad0b023fa28faf8862ff2d0b171381c8bd278c3  open62541-v1.3.15-git4.tar.gz
 sha256  fab3dd6bdab226f1c08630b1dd917e11fcb4ec5e1e020e2c16f83a0a13863e85  LICENSE

package/open62541/open62541.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-OPEN62541_VERSION = v1.3.12
+OPEN62541_VERSION = v1.3.15
 OPEN62541_SITE_METHOD = git
 OPEN62541_SITE = https://github.com/open62541/open62541.git
 OPEN62541_GIT_SUBMODULES = YES