Support skaffold fix —version skaffold/v1

[dgageot]

Fixes #3613

Also took the opportunity to:

• improve the code a bit
• add more unit tests
• add examples of usage for skaffold fix
• improve error messages

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

[codecov]

Codecov Report

Merging #4016 into master will increase coverage by 0.02%.
The diff coverage is 85.29%.

Impacted Files	Coverage Δ
pkg/skaffold/runner/generate_pipeline.go	0.00% <0.00%> (ø)
pkg/skaffold/schema/versions.go	82.75% <86.36%> (+7.75%)	⬆️
cmd/skaffold/app/cmd/fix.go	70.58% <87.50%> (+2.84%)	⬆️
cmd/skaffold/app/cmd/find_configs.go	45.71% <100.00%> (ø)
cmd/skaffold/app/cmd/runner.go	75.00% <100.00%> (ø)
pkg/skaffold/schema/latest/upgrade.go	100.00% <100.00%> (ø)
...affold/kubernetes/portforward/kubectl_forwarder.go	65.85% <0.00%> (-2.44%)	⬇️

[container-tools-bot]

Please visit http://34.94.104.146:1313 to view changes to the docs.

[tejal29]

LGTM excpet for doc changes

1. http://34.94.104.146:1313/docs/references/cli/#skaffold-fix the description needs to change from
   "Update old configuration to newest schema version" to "Update old configuration to newest or specified schema version"

2. Not your fault, but on the CLI page, the description for skaffild fix is incomplete
   http://34.94.104.146:1313/docs/references/cli/

skaffold fix - to upgrade from

fixed