Point users to `.xyz` domain instead of `.network`.

[yonas]

The Your project is available at: message should point to the .xyz domain instead of .network.

Visiting the .network link returns a 404 error.

[namelessperson0]

I also faced the same issue.
After rad push,
The below is shown

 Your project is available at:

   (web) https://app.radicle.network/seeds/...

But, the link returns 404.
It should be below

 Your project is available at:

   (web) https://app.radicle.xyz/seeds/...

I think, the value is set below in

radicle-cli/sync/src/lib.rs

Line 21 in e2bbf2f

pub const GATEWAY_HOST: &str = "app.radicle.xyz";

but it looks fine there.

[yonas]

@namelessperson0 Does #265 fix this for you? I don't have time to test right now.