Fix CircleCI build

This brings it closer to astropy#48 as well

Author: Cadair

.circleci/config.yml

@@ -4,7 +4,7 @@
 #
 version: 2.1
 jobs:
-  build-docs:
+  build-preview:
     docker:
       - image: cimg/python:3.14
     steps:
@@ -22,3 +22,11 @@ jobs:
       - store_artifacts:
           path: /home/circleci/project/docs/_build/html
           destination: html
+
+
+workflows:
+  version: 2
+
+  theme-previews:
+    jobs:
+      - build-preview