package/cjson: security bump to version 1.7.18
Add NULL check to cJSON_SetValuestring() (CVE-2024-31755)
https://github.com/DaveGamble/cJSON/releases/tag/v1.7.18
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>