Improve YAML/JSON printers example by stripping managedFields from output

[DavidGamba]

Hi,

Thanks so much for these examples, I was wondering how to print YAML and your repo came up in my searches.

After trying your sample code I noticed that the managed fields where in the output whereas kubectl won't show that.

I found the upstream PR where they disabled it:
https://github.com/kubernetes/kubernetes/pull/96878/files

I put the two things combined in my code and thought I should return the favour and at least mention it:
https://github.com/DavidGamba/dgtools/blob/edd077ad00ff54fe8d6c2f525442981a6ec38617/kdecode/main.go#L108-L126

Regards