build(router_env): obtain workspace member package names from cargo_metadata more deterministically

[SanchithHegde]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

This PR updates the build script code to obtain cargo workspace member package names to use a better and more deterministic way to do so.

Previously, we used to perform string manipulation on the package ID format (obtained from the workspace_members field in cargo metadata --format-version=1), and the package ID format was not stabilized (until recently). The package ID format has been stabilized in Rust 1.77, and the stabilized format breaks our existing build scripts. This PR updates the build script code to instead obtain the workspace member package names using the Metadata::workspace_packages() method that the cargo_metadata crate provides.

Motivation and Context

This would fix builds from breaking once Rust 1.77 is released as the stable version on March 21st, 2024.

Fixes #4137.

How did you test it?

cargo run was successful with both Rust 1.76 and 1.77 (although with warnings).

I installed the Rust 1.77 toolchain by following the instructions from the Rust 1.77.0 pre-release testing blog post.

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible
• I added a CHANGELOG entry if applicable