Remove circle ci configuration from gh pages

We removed Circle CI from this repo, as we can do everything
from github actions. There is no point in keeping this
configuration here. Removing.

.circleci/config.yml

@@ -1,16 +0,0 @@
-version: 2.1
-jobs:
-  build:
-    machine: true
-    steps:
-      - run: "echo skip"
-
-workflows:
-  version: 2
-  ignore:
-    jobs:
-      - build:
-          filters:
-            branches:
-              ignore:
-                - gh-pages