chore(deps): update module sigs.k8s.io/structured-merge-diff/v4 to v6

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

go.mod

@@ -6,7 +6,7 @@ go 1.23.0
 // please place any replace statements here at the top for visibility and add a
 // comment to it as to when it can be removed
 
-replace sigs.k8s.io/structured-merge-diff/v4 => sigs.k8s.io/structured-merge-diff/v4 v4.7.0
+replace sigs.k8s.io/structured-merge-diff/v4/v6 => sigs.k8s.io/structured-merge-diff/v4 v6.0.0
 
 require (
 	github.com/cert-manager/cert-manager v1.17.1