feat: replace pandoc plugin

[sys9kdr]

Summary

Description:

• Tool repo URL: https://github.com/jgm/pandoc
• Plugin repo URL: https://github.com/sys9kdr/asdf-pandoc

ref #995

Checklist

• Format with scripts/format.bash
• Test locally with scripts/test_plugin.bash --file plugins/<your_new_plugin_name>
• Your plugin CI tests are green
  • Tip: use the plugin_test action from asdf-actions in your plugin CI

[sys9kdr]

I'll try to fix the fbrisset/asdf-pandoc instead of replace.