fix: the longstanding bug on PRs: "We do not build CI environments."

[dalin-]

Fixes #67

[mdlutz24]

I don't see that this hurts anything, other than slightly slowing down branch build rejections, so I would lean towards committing it if it is useful to someone, but the linked issues are all many years old, and I've never run into this issue ever, as many projects I've set up in circle and pull requests I've made, so my gut says it's an outdated and unneeded fix. Do you have any examples of when this has occurred? I recall seeing in slack a while back that you ran into this issue repeatedly on a specific project. Maybe there is a project setup difference between how you and I set up circle projects that we could identify, document and learn from.

[dalin-]

On 4K GitHub/CircleCI I run into this bug rarely these days. We just moved NYU Stern Public to a client-owned repo, using the free tier of CircleCI. There we were running into this bug on 95% of builds. I just invited you there.

On any build for setup-environment-vars you'll see

Double checking for PR on NYUSTERN-1161-spacing-pt-7 to work around Circle platform bug.
contacted GitHub
Found PR 8

So I suspect it's one of two things:

• On the free tier, we're more likely to run into some race condition.
• I see on many 4K projects Bender has full admin access. Here I've only given him Read access.

[dalin-]

I just ran into this on Stateweb:
https://app.circleci.com/pipelines/github/fourkitchens/aft-stateweb/1946/workflows/714b2171-362f-4a71-bb65-9ec9897cbeb2/jobs/7244

Here rerunning the build fixed the problem:
https://app.circleci.com/pipelines/github/fourkitchens/aft-stateweb/1946/workflows/99220b17-5d50-4c77-8d19-144d9d74c79b/jobs/7248