Support installing/upgrading rye from github, in stead of rye.astral.sh

[CleanAir777]

Hello,

rye looks like a very promising tool, which I would like to use.

At home, that works fine. But at work, I am in an environment where I can't access a site on the Internet, unless it is whitelisted.

I can see that rye is communicating with rye.astral.sh, which is unrerachable at work. Github.com however, is reachable.

It would be very nice if it would be possible to tell rye not to use rye.astral.sh, but access github in stead. Or at the very least skip trying to communicate with rye.astral.sh, possibly after a timeout. Now, it just waits and times out after some time, and aborts the operation.

Using rye 0.41.0 on Linux