Shows wrong versions and error in Cargo.toml for platform specific dependencies

[RogueMacro]

Description
I ran into this issue when following a tutorial on gfx-hal, where I need a different backend crate for vulkan, metal, etc.

To Reproduce
Here is an example of the syntax I use:

[target.'cfg(target_os = "macos")'.dependencies.backend]
package = "gfx-backend-metal"
version = "0.9.1"

Expected behavior
I would expect it to approve this, since this is the latest version and it compiles fine.

Screenshots

Operating System:

• OS: Windows 10
• Version 21H1

Cause of bug
The reason this fails is because it looks for the crate 'backend' from [target.'cfg(target_os = "macos")'.dependencies.backend] instead of the package field. Which I confirmed because the 'backend' crate actually has the versions the crates extensions suggested to me.