impl FromLua for serde_json::Value

[lightsing]

This pull request introduces the implementation of the FromLua trait for serde_json::Value. This will allow smooth conversion from Lua values to serde_json values and get rid of the 'lua lifetime, providing better integration and flexibility.

Details:

1. Added a new feature flag for json:
   A new feature flag named json has been added, dependent on both the serialize feature and the serde_json crate. This allows the conditional compilation of the new implementation, ensuring backward compatibility.

2. Updated Cargo.toml:

   • Added serde_json as an optional dependency, with version "1.0".

3. Updated src/value.rs:

   • Added an implementation block for FromLua trait for serde_json::Value.
   • Inside the from_lua method, a value of Lua type is converted to a serde_json::Value, handling any potential conversion errors and wrapping them into the Error::FromLuaConversionError.

[ElhamAryanpur]

this is amazing