fix(deps): update module sigs.k8s.io/kustomize/api to v0.21.0 (#107)

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

Author: renovate[bot]

go.mod

@@ -20,7 +20,7 @@ require (
 	k8s.io/apimachinery v0.34.1
 	k8s.io/utils v0.0.0-20251002143259-bc988d571ff4
 	sigs.k8s.io/controller-runtime v0.22.4
-	sigs.k8s.io/kustomize/api v0.20.1
+	sigs.k8s.io/kustomize/api v0.21.0
 	sigs.k8s.io/kustomize/kyaml v0.21.0
 	sigs.k8s.io/yaml v1.6.0
 )

go.sum

@@ -299,8 +299,8 @@ sigs.k8s.io/controller-runtime v0.22.4 h1:GEjV7KV3TY8e+tJ2LCTxUTanW4z/FmNB7l327U
 sigs.k8s.io/controller-runtime v0.22.4/go.mod h1:+QX1XUpTXN4mLoblf4tqr5CQcyHPAki2HLXqQMY6vh8=
 sigs.k8s.io/json v0.0.0-20250730193827-2d320260d730 h1:IpInykpT6ceI+QxKBbEflcR5EXP7sU1kvOlxwZh5txg=
 sigs.k8s.io/json v0.0.0-20250730193827-2d320260d730/go.mod h1:mdzfpAEoE6DHQEN0uh9ZbOCuHbLK5wOm7dK4ctXE9Tg=
-sigs.k8s.io/kustomize/api v0.20.1 h1:iWP1Ydh3/lmldBnH/S5RXgT98vWYMaTUL1ADcr+Sv7I=
-sigs.k8s.io/kustomize/api v0.20.1/go.mod h1:t6hUFxO+Ph0VxIk1sKp1WS0dOjbPCtLJ4p8aADLwqjM=
+sigs.k8s.io/kustomize/api v0.21.0 h1:I7nry5p8iDJbuRdYS7ez8MUvw7XVNPcIP5GkzzuXIIQ=
+sigs.k8s.io/kustomize/api v0.21.0/go.mod h1:XGVQuR5n2pXKWbzXHweZU683pALGw/AMVO4zU4iS8SE=
 sigs.k8s.io/kustomize/kyaml v0.21.0 h1:7mQAf3dUwf0wBerWJd8rXhVcnkk5Tvn/q91cGkaP6HQ=
 sigs.k8s.io/kustomize/kyaml v0.21.0/go.mod h1:hmxADesM3yUN2vbA5z1/YTBnzLJ1dajdqpQonwBL1FQ=
 sigs.k8s.io/randfill v1.0.0 h1:JfjMILfT8A6RbawdsK2JXGBR5AQVfd+9TbzrlneTyrU=