package/libubox: bump version to 551d75b

Changelog:

  2e52c7e libubox: fix BLOBMSG_CAST_INT64 (do not override BLOBMSG_TYPE_DOUBLE)
  870acee tests: cram: test_base64: fix failing tests
  4d8995e tests: cram: test_base64: really fix failing tests
  551d75b libubox: tests: add more blobmsg/json test cases

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/libubox/libubox.hash

@@ -1,2 +1,2 @@
 # Locally calculated
-sha256  e383caf80a241e9711ab0c58a5e8f4d16479693be1e44ffb6cc716a185e7e303  libubox-5bc0146a1d6474d339c4ade9a227f32cc27a8b93-br1.tar.gz
+sha256  c6bac8baa7525b2d35eb22edeb5722c098370794d00e8859ef1a0bdfd8716151  libubox-551d75b5662cccd0466b990d58136bdf799a804d-br1.tar.gz

package/libubox/libubox.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-LIBUBOX_VERSION = 5bc0146a1d6474d339c4ade9a227f32cc27a8b93
+LIBUBOX_VERSION = 551d75b5662cccd0466b990d58136bdf799a804d
 LIBUBOX_SITE = https://git.openwrt.org/project/libubox.git
 LIBUBOX_SITE_METHOD = git
 LIBUBOX_LICENSE = ISC, BSD-3-Clause