Cargo workspace support.

[martinfrances107]

It looks like parsing of Cargo.toml files in the context of workspaces does not work.

That is parsing does not yet support workspaces.

when I supply a valid Cargo.toml file ( cargo check report the definitions are valid )

BUT I make reference to values listed in the root workspace as follows

 authors = { workspace = true }
 categories = { workspace = true }
 edition = { workspace = true }

Then I see errors like this

Caused by: failed to parse manifest at XX/rust_d3_geo/examples/globe/canvas/Cargo.toml

Caused by: invalid type: map, expected a sequence for key package.authors