Workspace: Inherit project-oriented Cargo.toml attributes

[behnam]

Having a workspace set up for multiple related crates, there's usually a big chunk of Cargo.toml attributes which need to be copy-pasted across all instances.

For example, in UNIC, we have (at least) these lines in all (published) Cargo.toml files:

[badges]
maintenance = { status = "actively-developed" }
is-it-maintained-issue-resolution = { repository = "open-i18n/rust-unic" }
is-it-maintained-open-issues = { repository = "open-i18n/rust-unic" }
appveyor = { repository = "open-i18n/rust-unic", branch = "master", service = "github" }
travis-ci = { repository = "open-i18n/rust-unic", branch = "master" }

Most of such properties are project-specific, but not crate-specific. For example, an indicator of that would be the fact that the share the same repository value.

It would be great if we could actually have such project-oriented attributes inherit from the workspace's main Cargo.toml, and do no need to maintain copies of them.

Wdyt?

[behnam]

Oops, wrong repo. Filed here: rust-lang/cargo#6828