Update cJSON

[DL6ER]

What does this implement/fix?

Update bundled cJSON from 1.7.15 -> 1.7.17 released yesterday.

Fixes:

• Fix null reference in cJSON_SetValuestring(CVE-2023-50472), see add NULL checkings DaveGamble/cJSON#809
• Fix null reference in cJSON_InsertItemInArray(CVE-2023-50471), see add NULL checkings DaveGamble/cJSON#809 and fix error in null checkings DaveGamble/cJSON#810

Features:

• Add an option for ENABLE_CJSON_VERSION_SO in CMakeLists.txt, see add an option for ENABLE_CJSON_VERSION_SO in CMakeLists.txt DaveGamble/cJSON#534
• Add cmake_policy to CMakeLists.txt, see Makefile problem with gcc < 4.9 Ubuntu DaveGamble/cJSON#163
• Add cJSON_SetBoolValue, see cJSON_SetBoolValue plus test DaveGamble/cJSON#639
• Add meson documentation, see Add meson documentation DaveGamble/cJSON#761

Full changelog

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Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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