Fix 404 issue with the reference docs

Related to the previous commit.

Author: sobychacko

spring-kafka-docs/src/main/antora/antora-playbook.yml

@@ -6,7 +6,6 @@ antora:
     - require: '@springio/antora-extensions/latest-version-extension'
     - require: '@springio/antora-extensions/inject-collector-cache-config-extension'
     - '@antora/collector-extension'
-    - '@antora/atlas-extension'
     - require: '@springio/antora-extensions/root-component-extension'
       root_component_name: 'kafka'
       # FIXME: Run antora once using this extension to migrate to the Asciidoc Tabs syntax