ffmpeg struggles converting gifs with odd dimensions

[JamesLMilner]

Hey! Firstly, thanks for the great project.

I am noticing an issue with odd shaped gifs :

[11ty] Problem writing Eleventy templates: (more in DEBUG output)
[11ty] > Having trouble writing template: _site/posts/cancelling-requests/index.html

`TemplateWriterWriteError` was thrown
[11ty] > Failed executing '/home/james/Code/jameslmilner.com-11ty/node_modules/ffmpeg-static/ffmpeg' -y -v error -i '_site/img/posts/abort/abortable-fetch.gif' -filter_complex '[0:v] fps=15, scale=iw:-2' -vsync 0 -f mp4 -pix_fmt yuv420p '_site/img/posts/abort/abortable-fetch.mp4' with [libx264 @ 0x6970fc0] width not divisible by 2 (1203x492)
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

`Error` was thrown:
[11ty]     Error: Failed executing '/home/james/Code/jameslmilner.com-11ty/node_modules/ffmpeg-static/ffmpeg' -y -v error -i '_site/img/posts/abort/abortable-fetch.gif' -filter_complex '[0:v] fps=15, scale=iw:-2' -vsync 0 -f mp4 -pix_fmt yuv420p '_site/img/posts/abort/abortable-fetch.mp4' with [libx264 @ 0x6970fc0] width not divisible by 2 (1203x492)
    Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

If I change

eleventy-high-performance-blog/_11ty/video-gif.js

Line 44 in fd0dcd8

"[0:v] fps=15, scale=iw:-2",

to:

    "[0:v] fps=15, scale=trunc(iw/2)*2:trunc(ih/2)*2",

It removes the errors, but I think that doesn't perform any scaling as was originally intended. I could look at the correct rounding logic to figure out how to keep the -2 scaling and raise a PR if it would be helpful. Let me know!