[PATCH setup] Add --allow-test-versions

[Jon Turney]

On 20/04/2021 15:37, David Allsopp via Cygwin-apps wrote:
> Attached adds -t/--allow-test-packages to Setup which controls the initial
> state of the "Test" checkbox.
> 
> Motivation is to allow one CI cron job to be installing test versions of
> packages, then we can help identify things like [1] before they're released.

Nice.  Thanks.

> +static BoolOption AllowTestOption (false, 't', "allow-test-packages", "Permit installation of package versions marked test");

The only quibble I have is the help text here.  The user has always been 
permitted to choose test packages, this checkbox allows setup to decide 
to use them itself.

So maybe something like "Consider package versions marked test".