package/libyang: security bump to version 1.0.240

package/libyang: security bump to version 1.0.240

Fixes the following security issues:

- CVE-2021-28902: In function read_yin_container() in libyang <= v1.0.225,
  it doesn't check whether the value of retval->ext[r] is NULL.  In some
  cases, it can be NULL, which leads to the operation of
  retval->ext[r]->flags that results in a crash.

- CVE-2021-28903: A stack overflow in libyang <= v1.0.225 can cause a denial
  of service through function lyxml_parse_mem().  lyxml_parse_elem()
  function will be called recursively, which will consume stack space and
  lead to crash.

- CVE-2021-28904: In function ext_get_plugin() in libyang <= v1.0.225, it
  doesn't check whether the value of revision is NULL.  If revision is NULL,
  the operation of strcmp(revision, ext_plugins[u].revision) will lead to a
  crash.

- CVE-2021-28905: In function lys_node_free() in libyang <= v1.0.225, it
  asserts that the value of node->module can't be NULL.  But in some cases,
  node->module can be null, which triggers a reachable assertion (CWE-617).

- CVE-2021-28906: In function read_yin_leaf() in libyang <= v1.0.225, it
  doesn't check whether the value of retval->ext[r] is NULL.  In some cases,
  it can be NULL, which leads to the operation of retval->ext[r]->flags that
  results in a crash.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>