do not override default layout

Author: hauner

docs/modules/ROOT/pages/index.adoc

@@ -1,6 +1,5 @@
 :author: Martin Hauner
 :page-title: openapi-processor-json
-:page-layout: default
 :page-aliases: current@json:ROOT:index.adoc, latest@json:ROOT:index.adoc
 :badge-license: https://img.shields.io/badge/License-Apache%202.0-blue.svg?labelColor=313A42
 :badge-ci: https://github.com/hauner/openapi-processor-json/workflows/ci/badge.svg