Add json output to skaffold schema list

[dgageot]

Fixes #4382

Signed-off-by: David Gageot [email protected]

[codecov]

Codecov Report

Merging #4385 into master will increase coverage by 0.03%.
The diff coverage is 96.00%.

@@            Coverage Diff             @@
##           master    #4385      +/-   ##
==========================================
+ Coverage   71.73%   71.77%   +0.03%     
==========================================
  Files         325      325              
  Lines       12572    12594      +22     
==========================================
+ Hits         9019     9039      +20     
- Misses       2977     2979       +2     
  Partials      576      576              

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/schema/list.go	91.30% <95.23%> (-8.70%)	⬇️
cmd/skaffold/app/cmd/schema.go	82.60% <100.00%> (+2.60%)	⬆️

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