changed sql types access to pub

[IDEA-godwin]

the trait SqlTypes is not pub.

I needed to define a method parameter to values that have the SqlType trait but noticed that the sdk does not exposes the trait, making it impossible to do as I can not use ws_sdk::database::sql_types::SqlType

[Liuhaai]

Hi IDEA-godwin, thx for the pr. Our host only supports serveral params currently. So SqlType isn't exposed at the first. Actually, you can add an implementation as a pr directly if it's common https://github.com/machinefi/w3bstream-wasm-rust-sdk/blob/main/src/database/sql_types.rs#L82
it would be great if you could share your implementation for SqlType trait