Re-rebuilding TF2.8 image: 369 patches

I wrote previously about rebuilding the TF2.8 image to patch vulnerabilities.

I noticed the issue scanner had crept up again. So I rebuilt the container again, using the same dockerfiles (etc).

The upstream changes (e.g. in Ubuntu 22.04) pulled in 369 security fixes. 🎉

Along the way, I regretted that the tensorflow-2.8.4-redux repo doesn't have automatic container building. I can't build it locally any longer as it needs x86_64 but I have arm64. 😓 I was able to build it in Cloud Shell easily enough for now.