`crates_vendor` ignores package renames in Cargo.toml for aliases

For example, this entry in Cargo.toml:

```
[dependencies.async_trait]
package = "async-trait"
version = "0.1.51"
default_features = false
features = []
```

Will generate an alias such as:

```
alias(
name = "async-trait",
actual = "@crates__async-trait-0.1.57//:async_trait",
tags = ["manual"],
)
```

Whereas I'd expect the name to be `async_trait` (vs `async-trait`).