Fix issues between reference counting and the custom `JSON.parse` implementation

[saulecabrera]

Description of the change

This change contains two commits, each with a clear description of the change.

Checklist

• [x] I've updated the relevant CHANGELOG files if necessary. Changes to javy-cli and javy-core do not require updating CHANGELOG files.
• [x] I've updated the relevant crate versions if necessary. Versioning policy for library crates
• [x] I've updated documentation including crate documentation if necessary.

[saulecabrera]

I'm still figuring out the CI failures, maybe it's something with GH actions. Locally everything passes 🤷🏽

[saulecabrera]

I'm still figuring out the CI failures, maybe it's something with GH actions. Locally everything passes 🤷🏽

Err - a missing cfg and clippy