Work around registry git-fetch errors

Hi there, I am trying to use cargo edit behind a corporate proxy, but got such error:

```
Updating 'https://github.com/rust-lang/crates.io-index' index
Command failed due to unhandled error: SSL error: syscall failure: Bad file descriptor; class=Os (2); code=Certificate (-17)
```

I have already set my git to ignore ssl checking with `http.sslverify=false`. And in cargo as well with:

```
[http]
check-revoke = false
```

But it seems these settings are not picked up by cargo edit. Is that true? How can I configure cargo edit to ignore the ssl cert checking too? Thank you!

Reproduce the cargo edit registry fetch behind a corporate proxy using the reported git and Cargo settings, then trace how cargo-edit invokes the registry fetch. Determine whether those settings are ignored and document or implement the supported configuration; done means the SSL error has a clear, verified workaround.

Written by the indexing model from the issue text.