Change json_object name to avoid conflict with jansson lib.

[MisterRaindrop]

closes: #ISSUE_Number

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Change logs

kernal the name “json_object” conflicts with the name of the jansson library. To avoid this conflict, change the name to pg_json_object.

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Hiiii, @MisterRaindrop welcome!🎊 Thanks for taking the effort to make our project better! 🙌 Keep making such awesome contributions!