fix(deps): update module golang.org/x/sync to v0.21.0

Author: renovate[bot]

go.mod

@@ -13,7 +13,7 @@ require (
 	go.datum.net/network-services-operator v0.21.10-0.20260528021428-b0f2347f5359
 	go.miloapis.com/milo v0.25.2-0.20260528192736-e4258524ad42
 	golang.org/x/crypto v0.45.0
-	golang.org/x/sync v0.18.0
+	golang.org/x/sync v0.21.0
 	google.golang.org/protobuf v1.36.11
 	k8s.io/api v0.35.0
 	k8s.io/apimachinery v0.35.0

go.sum

@@ -195,6 +195,8 @@ golang.org/x/oauth2 v0.30.0 h1:dnDm7JmhM45NNpd8FDDeLhK6FwqbOf4MLCM9zb1BOHI=
 golang.org/x/oauth2 v0.30.0/go.mod h1:B++QgG3ZKulg6sRPGD/mqlHQs5rB3Ml9erfeDY7xKlU=
 golang.org/x/sync v0.18.0 h1:kr88TuHDroi+UVf+0hZnirlk8o8T+4MrK6mr60WkH/I=
 golang.org/x/sync v0.18.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
+golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
 golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/term v0.37.0 h1:8EGAD0qCmHYZg6J17DvsMy9/wJ7/D/4pV/wfnld5lTU=