Functions: Added support for Node.js 20

Nhost has introduced an option for users to select between Node.js 18 and Node.js 20 as their functions runtime, which can be easily configured in the nhost.toml file. By updating the version number in the configuration, users can switch their Node.js environment and verify the change by invoking a function, such as an example echo function, which returns the Node.js version being used. This new capability aims to facilitate the homogenization of runtime environments and simplify the setup process for users. For further information, users are encouraged to consult the documentation.