docker: Update libexec archive to 2023-04-18/v9

[dnadlinger]

pdfsizeopt currently fails on many of my PDFs with a sam2p "bad palette size" error, presumably fixed in https://github.com/pts/imgdataopt/commit/a245e29c04e007d48a6242cdf770f14c690cbce7. Binaries with that fix already exist, but the official Docker images still use an old version.

Using an image built from this commit fixes the issue locally, but it would be great if it could be merged/pushed to the official registry.