Kroki Arbitrary File Read/Write

In short, I've found a potentially weird bug in `asciidoctor` that could lead to arbitrary file read/write in `asciidoctor-kroki` even though Gitlab have already made an attempt to disable `kroki-plantuml-include`

module Gitlab
  # Parser/renderer for the AsciiDoc format that uses Asciidoctor and filters
  # the resulting HTML through HTML pipeline filters.
  module Asciidoc
    MAX_INCLUDE_DEPTH = 5
    MAX_INCLUDES = 32
    DEFAULT_ADOC_ATTRS = {
        'showtitle' => true,
        'sectanchors' => true, …