exclude Node 17.x as supported version

[Conduitry]

Closes #8173. The >=16.14 range also includes Node 17, which (apparently at least in some versions) doesn't support the three-argument version of util.inspect.custom. People shouldn't be using Node 17 anyway. I think we can make this change as a fix rather than as a breaking change.

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[Conduitry]

I really can't tell what all these test and deployment failures are about. I don't see how they could be related to this change.

[dummdidumm]

(I approved because I think Node 17 being a non-LTS line and unsupported at this point is a good-enough reason to make this change right now when 1.0 is so fresh still; it will probably break right away for anyone using it anyway, as the issue shows)

[colinhowells]

Question about Cloudflare – right now they ask for 17 for Pages projects, wondering what the impact there might be

[Conduitry]

That's annoying. Thanks. I've opened a PR cloudflare/cloudflare-docs#7043

[colinhowells]

I'm also not sure if anything above 17 is available, last time I tried 18 it wasn't. Let me try a build now ...

Nope: Failed to install node version '18'

edit: their container is a bit weird (Node 12 by default, PHP 5.6?), and they know this, but it's taking a while for them to update everything in it, so this may be a good prod to make that happen

[Conduitry]

Do you know what version of Node 16 you get if you specify NODE_VERSION=16? Is it at least 16.14, the minimum version needed by SvelteKit?

[colinhowells]

Let's see ... 16.19.0.

I can go around to my existing Pages projects and switch everything to 16, just in case it takes a while for Flare to get on it.

When you ask for 17 you get 17.9.1, fyi