Add cargo watch to rust installation

[nicraMarcin]

vscode-dev-containers/script-library/rust-debian.sh

Line 215 in 9ead9df

Hi, is it possible to add cargo install cargo-watch to this script?

[bamurtaugh]

Thanks for opening an issue!

Our team has been actively working on an updated plan for community contributions and this repo moving forward, which we've now outlined in this issue: #1589. This includes moving to new repos for images (https://github.com/devcontainers/images) and Features (https://github.com/devcontainers/features), and we anticipate to have a similar repo and process for templates/definitions.

Please feel free to open an issue on the new Rust Feature, and let me know if you have any questions. Thank you!