Upgrade cargo-xwin to unify rustls versions

[kornelski]

Fixes #1671

Currently cargo install --locked pulls in a yanked dependency, and the default cargo install breaks due to fragility of ureq's API. Either way it doesn't look good.

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[sentialx]

plz merge, cross-compiling to windows doesn't work currently

[messense]

plz merge, cross-compiling to windows doesn't work currently

@sentialx we're still waiting for a new ureq 2.x release, consider asking ureq for a new release if you want to push this forward.

[sentialx]

@messense xwin no longer uses ureq due to this issue: Jake-Shadle/xwin#141
Disregard my previous comment, this PR won't fix the issue, but updating xwin to 0.6.6-rc.1 should.

[messense]

It's unlikely we will upgrade to a xwin version that uses reqwest, there is no point in pulling in two http client library in maturin, and we'd like to avoid reqwest because it also pulls in the whole tokio stack which bloats maturin by a lot in terms of compilation time.

[sentialx]

So cross-compilation for Windows will never work in maturin?

[messense]

Honestly I'm not sure what was your issue with it, it's working fine for me, Jake-Shadle/xwin#141 is a flaky issue, it's not happening all the time, in fact it never occurred locally on my dev machine.

[sentialx]

It is happening for me all the time and same for others as seen by my issue reactions.

[messense]

It is happening for me all the time

Then please consider investing some time to help debugging the root cause of the issue.