Conda-forge.github.io: Upgrade to 4 total concurrent appveyor jobs until end of compiler migration

[scopatz]

@conda-forge/core

This PR falls under "all other voting items", please vote and/or comment on this PR. This PR needs 50% of core to vote yea to pass. To vote please leave Approve (yea) or Request Changes (nay) reviews. If you would like changes to the current language please leave a comment or push to this branch. This vote will end on 2018/10/23.

This aims to spend some of our financial resources on purchasing 2 more (for a total of 4) concurrent Appveyor jobs until the end of the compiler migration. This is expected to cost $50 / month. @scopatz will pay and be reimbursed by Numfocus.

[CJ-Wright]

I guess we need a governance doc variant for issues (since review votes don't exist)? Although I would actually prefer this in a PR into a document which is a running tally of proposals (or a folder of proposals) since that allows us to track what is going on in a central place which is easy to find.

[scopatz]

@jakirkham @msarahan @loriab @jjhelmus @ericdill - are any of you interested in supporting this? We are one vote away from this passing.

[scopatz]

OK! This passes! I'll go purchase the appveyor now.

[mwcraig]

Thanks, @scopatz!