Error message disappears too quickly

I deleted all files in juliaup, then from the command prompt, then ran `julia`.

```
No Julia version for channel 1 is installed on this system. Run:

juliaup update

to install Julia 1, the latest Julia version for the current channel.
```

Windows console windows are closed as soon as their program exits. I suggest adding a "press any key to exit" read prompt to ensure the window stays open so the message can be read.

_Originally posted by @BioTurboNick in https://github.com/davidanthoff/juliaup/issues/36#issuecomment-848779449_

Start by tracing the CLI path used when `julia` is run from a Windows command prompt with no Julia version installed. Reproduce the reported message and confirm that the console currently closes immediately; done means the message remains readable before the process exits.

Written by the indexing model from the issue text.