Do not crash with Cargo workspaces

[pombredanne]

We need to support correctly workspaces:
https://doc.rust-lang.org/book/ch14-03-cargo-workspaces.html

A workspace is a set of packages that share the same Cargo.lock and output directory.

Here is an example: https://github.com/tauri-apps/tauri/blob/dev/Cargo.toml

[AyanSinhaMahapatra]

This is fixed with #3602

See scan below:
tauri-dev-scan-results.json.txt