Replace gopkg.in/yaml.v3 with sigs.k8s.io/yaml in write_test.go to match
the marshaling library used by WriteConfig. The sigs.k8s.io/yaml library
uses JSON struct tags, enabling proper round-trip serialization of configs
with custom unmarshaling logic like ConnectorConfig.
Signed-off-by: Bryan Frimin <bryan@getprobo.com>
