docs: Update links in commands-demo.md

[fscholdei]

Some links, such as podman-generate or podman-network, led nowhere. I have updated these outdated links.

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[Honny1]

Thanks, LGTM.

[mheon]

I wonder if we shouldn't just remove this document. In the very old days, each command had a demo, but the asciinemas got lost, and now only 1 or 2 have demos.

[Honny1]

I wonder if we shouldn't just remove this document. In the very old days, each command had a demo, but the asciinemas got lost, and now only 1 or 2 have demos.

That's a good point. Maybe we should only link to some interesting talks with demos, for example:

• Replacing Docker with Podman https://www.youtube.com/watch?v=YkBk52MGV0Y
• Container Security https://www.youtube.com/watch?v=hH9kzvDE_gM
• Container tools https://www.youtube.com/lwatch?v=40ynATurI7k
• Container runtime security https://www.youtube.com/watch?v=XH2xqN1m0mw