textproc/rubygem-asciidoctor-pdf: Allow work with rubygem-prawn-svg 0.33.0+

Obtained from: https://github.com/asciidoctor/asciidoctor-pdf/commit/cd71092a5c5c86b9770359a0f1bd7c60b9dce7ea

PR: 275957
Approved by: maintainer timeout

(cherry picked from commit af747c350b9477460c7d606dc0a2a801ce803663)