Rename spec.sync to spec.quickSync

[na-ga]

What this PR does / why we need it:

sync field has been changed to a quickSync field

• https://pipecd.dev/docs/user-guide/configuration-reference/#kubernetesquicksync

Which issue(s) this PR fixes:

• Rename Sync to QuickSync #572

Does this PR introduce a user-facing change?:

NONE

[pipecd-bot]

Welcome @na-ga!

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[na-ga]

/cla sign

[pipecd-bot]

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[nghialv]

Thank you.
/approve

[pipecd-bot]

This pull request is APPROVED by nghialv.

Approvers can cancel the approval by writing /approve cancel in a comment. Any additional commits also will change this pull request to be not-approved.

[nakabonne]

Thank you for your contribution!

[pipecd-bot]

Code coverage for golang is 33.80%. This pull request does not change code coverage.