Activate more linters

[dgageot]

• dogsled: Checks assignments with too many blank identifiers (e.g. x, _, _, _, := f())
• nakedret: Finds naked returns in functions greater than a specified function length
• whitespace: Tool for detection of leading and trailing whitespace

Signed-off-by: David Gageot david@gageot.net

[codecov]

Codecov Report

Merging #3057 into master will not change coverage.
The diff coverage is n/a.

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/config.go	100% <ø> (ø)	⬆️
pkg/skaffold/build/parallel.go	94.36% <ø> (ø)	⬆️
pkg/skaffold/build/local/local.go	33.33% <ø> (ø)	⬆️
pkg/skaffold/jib/jib_gradle.go	100% <ø> (ø)	⬆️
pkg/skaffold/build/cluster/secret.go	36.2% <ø> (ø)	⬆️
pkg/skaffold/debug/debug.go	43.33% <ø> (ø)	⬆️
pkg/skaffold/build/custom/custom.go	62.5% <ø> (ø)	⬆️
pkg/skaffold/docker/client.go	73.73% <ø> (ø)	⬆️
pkg/skaffold/docker/auth.go	55.76% <ø> (ø)	⬆️
pkg/skaffold/build/cache/hash.go	72.3% <ø> (ø)	⬆️
... and 76 more

[tejal29]

Thanks @dgageot.
Can you please specify what each of the linters you activated do?

    - dogsled
    - nakedret
    - whitespace

[dgageot]

@tejal29 description added

[balopat]

Nice, sounds good, thank you!