Upgrade Jib to 2.1.0

[chanseokoh]

No description provided.

[codecov]

Codecov Report

Merging #3728 into master will increase coverage by 1.81%.
The diff coverage is 82.08%.

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/diagnose.go	35% <ø> (ø)	⬆️
cmd/skaffold/app/cmd/credits/statik/statik.go	100% <ø> (ø)
cmd/skaffold/app/cmd/credits/export.go	0% <0%> (ø)	⬆️
cmd/skaffold/app/cmd/schema/list.go	100% <100%> (ø)
cmd/skaffold/app/cmd/init.go	100% <100%> (+43.47%)	⬆️
cmd/skaffold/app/cmd/flags.go	100% <100%> (ø)	⬆️
cmd/skaffold/app/cmd/cmd.go	67.42% <50%> (+0.23%)	⬆️
cmd/skaffold/app/cmd/schema/print.go	80% <80%> (ø)
cmd/skaffold/app/cmd/schema.go	80% <80%> (ø)
pkg/skaffold/build/cluster/kaniko.go	0% <0%> (-55.13%)	⬇️
... and 118 more

Please update only in integration/examples if there are any unreleased changes to skaffold for consuming jib-2.1.0