Add PodMetrics as excluded resource by default

[Aracki]

r.APIResource.Kind is the only way to distinct Pod & PodMetrics because they have the same .Name.

[codecov-io]

Codecov Report

Merging #51 into master will increase coverage by 0.14%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #51      +/-   ##
==========================================
+ Coverage   41.96%   42.11%   +0.14%     
==========================================
  Files           9        9              
  Lines         386      387       +1     
==========================================
+ Hits          162      163       +1     
  Misses        202      202              
  Partials       22       22

Impacted Files	Coverage Δ
internal/client/client.go	23.91% <100%> (+0.55%)	⬆️
cmd/root.go	68.88% <100%> (ø)	⬆️

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[corneliusweig]

Hi @Aracki,

thanks for working on this! It makes sense to also filter by resource kind, so this is really nice. I just need to ask you to signoff your commits with git commit --amend --signoff.

[Aracki]

@corneliusweig Did that 👍

[corneliusweig]

Thanks again!