Update Appveyor's configuration

[mrkishi]

Follow up to #2970, also make sure we support node v8+ on Windows.

[Conduitry]

This seems good for now, but it might be nice sometime to switch to Travis's multi-OS builds and get rid of Appveyor.

[Conduitry]

Huh https://ci.appveyor.com/project/Rich-Harris/svelte/builds/25155137/job/2fquajgk0kt579hj I don't know what to make of that.

[shinnn]

I don't know what to make of that.

appveyor/ci#2921 hasn't been fixed yet.

[mrkishi]

Eek. Used the update path instead.

[shinnn]

I guess this || npm install fallback is not needed, because npm CLI update was backported to Node.js 8.

[mrkishi]

TIL!

[Conduitry]

Huh. After over a month v12 still isn't available in the standard way? Maybe this is another reason to move to Travis for this sooner rather than later.

[Rich-Harris]

How straightforward is it to get things up and running on Travis?

[Conduitry]

Here's the config I used for cheap-watch, and everything Just Worked. Although I'm realizing now that I'm not sure how this would deal with the custom element tests in puppeteer.

[paulocoghi]

@Conduitry

This seems good for now, but it might be nice sometime to switch to Travis's multi-OS builds and get rid of Appveyor.

I believe that Travis doesn't support Windows (at least not on the free version for open source projects). On my research to multi OS tests, I was able to test Linux and OSX on Travis with:

And Appveyor is my only option today for Windows tests.

Do your Windows tests on Travis also work on free accounts?

---

Although I'm realizing now that I'm not sure how this would deal with the custom element tests in puppeteer.

I'm using puppeteer on the tests of my library liven (that replace livereload and browser-sync), both on Travis and Appveyor with no issues, using the official method: https://jestjs.io/docs/en/puppeteer

[Conduitry]

I'm using a Windows build on Travis in the project I linked to in my previous comment, and I'm not paying them.

[paulocoghi]

Wow. Good to know!