Use more universal windows install instructions (#1811)
Recommend installing uv on windows with
```
powershell -c "irm https://astral.sh/uv/install.ps1 | iex"
```
instead of
```
irm https://astral.sh/uv/install.ps1 | iex
```
to support installing on cmd.exe, the classic non-powershell windows
command prompt.
See https://github.com/axodotdev/cargo-dist/issues/458 for background.
This will also be included in the next cargo-dist release.
I have confirmed this passes on
* Command Prompt
* Windows PowerShell
* PowerShell
* git bash
Closes #1750
CC @12932 this fixes the uv command prompt installation.
