chore: Migrate from gopkg.in/yaml.v3 to go.yaml.in/yaml/v3 (#2336)

The original gopkg.in/yaml.v3 was marked unmaintained (April 2025).
go.yaml.in/yaml/v3 is now maintained by the official YAML organization
and is a drop-in replacement with an identical API.

Signed-off-by: Davanum Srinivas <davanum@gmail.com>