Remove old doc build trigger from CI

.drone.yml

@@ -217,18 +217,3 @@ steps:
     when:
       status: failure
       event: pull_request
-
-  - name: trigger documentation build
-    image: plugins/downstream
-    settings:
-      server: https://ci.garrettmills.dev
-      token:
-        from_secret: drone_token
-      fork: false
-      last_successful: true
-      deploy: production
-      repositories:
-        - Extollo/docs@master
-    when:
-      status: success
-      event: tag