CI required even if CI is ignored

[lipkau]

Expected Behavior

Github allows a maintainer to merge a PR that does not change code in the web UI without elevating permissions

Current Behavior

Github requires CI to finish successfully, but CI ignores PRs that don't change code. This cases github's web UI to require admin permissions to merge the PR.

Possible Solution

Move the logic of what changes to ignore from AppVeyor's config to the build script

continues #122