Pandoc 3.2.1 update on LaTeX writer

[cderv]

It seems Pandoc 3.2.1 has big change on Writer

See https://github.com/jgm/pandoc/releases/tag/3.2.1

New method for ensuring images don’t overflow (jgm/pandoc#9660). Previously we relied on graphicx internals and made global changes to Gin to force images to be resized if they exceed textwidth. This approach is brittle and caused problems with \includesvg (see jgm/pandoc#9660). The new approach uses a new macro \pandocbounded that is now defined in the LaTeX template. (Thanks here to Falk Hanisch in mrpiggi/svg#60.) The LaTeX writer has been changed to enclose \includegraphics and \includesvg commands in this macro when they don’t explicitly specify a width or height. In addition, the writer now adds keepaspectratio to the \includegraphics or \includesvg options if height is specified without width, or vice versa. Previously, this was set in the preamble as a global option. Users should attend to the following compatibility issues:
If custom templates are used with the new LaTeX writer, they will have to be updated to include the new \pandocbounded macro, or an error will be raised because of the undefined macro.
Documents that specify explicit dimensions for an image may render differently, if the dimensions are greater than the line width or page height. Previously pandoc would shrink these images to fit, but the new behavior takes the specified dimensions literally. In addition, pandoc previously always enforced keepaspectratio, even when width and height were both specified, so images with width and height specified that do not conform to their intrinsic aspect ratio will appear differently.

Especially :

If custom templates are used with the new LaTeX writer, they will have to be updated to include the new \pandocbounded macro, or an error will be raised because of the undefined macro.

So we may need to include it when Pandoc 3.2.1 is used.

I'll run CI to see if we already detect problems: https://github.com/rstudio/rticles/actions/runs/9659732696