Pin deterministic-wasi-ctx dependency

[jeffcharles]

Description of the change

Pins the deterministic-wasi-ctx dependency to a particular version.

Why am I making this change?

Fixes #1182. deterministic-wasi-ctx requires a particular major version of wasmtime and that status quo setup will have the javy-codegen crate try to download the latest 4.x.x version of deterministic-wasi-ctx that may or may not depend on the same major version of wasmtime. Pinning the version of deterministic-wasi-ctx will ensure javy-codegen and deterministic-wasi-ctx depend on the same major version of wasmtime.

An alternative approach would be to switch deterministic-wasi-ctx back to depending on a range of wasmtime versions instead of a specific major version.

Checklist

• I've updated the default plugin import namespace and incremented the major version of javy-plugin-api if the QuickJS bytecode has changed.
• I've updated the relevant CHANGELOG files if necessary. Changes to javy-cli, javy-plugin, and javy-plugin-processing do not require updating CHANGELOG files.
• I've updated the relevant crate versions if necessary. Versioning policy for library crates
• I've updated documentation including crate documentation if necessary.