Windows build is supported in Circle CI

[haohanyang]

Description

Circle CI setup is missing in the docs.

My Circle CI workflow has successfully built windows wheels

Build log

https://app.circleci.com/pipelines/github/haohanyang/phreeqc/7/workflows/5b9a38bb-4849-4f2b-bed4-a2ec11f7b703/jobs/18

CI config

https://github.com/haohanyang/phreeqc/blob/master/.circleci/config.yml

[Czaki]

We have marked as supported only these types of CI runners that we have enabled in CI.

I'm not sure if our plan has enough minutes to enable such a build type. @joerick Could you check?

[joerick]

Last time we discussed this their OSS plan excluded Windows, but it looks like it includes it now.

We're now pooled into the pypa plan, so there shouldn't be a problem with build credits, if it's enabled. On second thoughts, the dashboard is a little confusing, but it seems that last month we used 108,767 out of 400,000 credits, so we should be okay on that.