fix(deps): update module github.com/kcp-dev/kcp/sdk to v0.28.3

Author: renovate[bot]

go.mod

@@ -10,7 +10,7 @@ require (
 	github.com/fluxcd/source-controller/api v1.7.4
 	github.com/go-logr/logr v1.4.3
 	github.com/google/gnostic-models v0.7.1
-	github.com/kcp-dev/kcp/sdk v0.28.1-0.20250926104223-cec2e15f24c6
+	github.com/kcp-dev/kcp/sdk v0.28.3
 	github.com/kcp-dev/logicalcluster/v3 v3.0.5
 	github.com/kcp-dev/multicluster-provider v0.2.0
 	github.com/openfga/api/proto v0.0.0-20251105142303-feed3db3d69d
@@ -22,6 +22,7 @@ require (
 	github.com/spf13/viper v1.21.0
 	github.com/stretchr/testify v1.11.1
 	golang.org/x/oauth2 v0.34.0
+	golang.org/x/sync v0.18.0
 	google.golang.org/grpc v1.77.0
 	google.golang.org/protobuf v1.36.10
 	k8s.io/api v0.34.2
@@ -109,7 +110,6 @@ require (
 	golang.org/x/crypto v0.44.0 // indirect
 	golang.org/x/exp v0.0.0-20251125195548-87e1e737ad39 // indirect
 	golang.org/x/net v0.47.0 // indirect
-	golang.org/x/sync v0.18.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/term v0.37.0 // indirect
 	golang.org/x/text v0.31.0 // indirect

go.sum

@@ -112,8 +112,8 @@ github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnr
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
 github.com/kcp-dev/apimachinery/v2 v2.0.1-0.20250728122101-adbf20db3e51 h1:l38RDS+VUMx9etvyaCgJIZa4nM7FaNevNubWN0kDZY4=
 github.com/kcp-dev/apimachinery/v2 v2.0.1-0.20250728122101-adbf20db3e51/go.mod h1:rF1jfvUfPjFXs+HV/LN1BtPzAz1bfjJOwVa+hAVfroQ=
-github.com/kcp-dev/kcp/sdk v0.28.1-0.20250926104223-cec2e15f24c6 h1:bOR4mdLD24VCJRrHxmtTh21AdbbzkBBKkEh0ngL+XTc=
-github.com/kcp-dev/kcp/sdk v0.28.1-0.20250926104223-cec2e15f24c6/go.mod h1:aC2BPGPvy8QtkI2gQNH9NfW6xpfGIKZkR93gy9O02BE=
+github.com/kcp-dev/kcp/sdk v0.28.3 h1:TS2nJOVBjenBd3fz1+y3aNrqZWqmakalNAIcQM9SukQ=
+github.com/kcp-dev/kcp/sdk v0.28.3/go.mod h1:8oZpWxkoMu2TDpx5DgdIGDigByKHKkeqVMA4GiWneoI=
 github.com/kcp-dev/logicalcluster/v3 v3.0.5 h1:JbYakokb+5Uinz09oTXomSUJVQsqfxEvU4RyHUYxHOU=
 github.com/kcp-dev/logicalcluster/v3 v3.0.5/go.mod h1:EWBUBxdr49fUB1cLMO4nOdBWmYifLbP1LfoL20KkXYY=
 github.com/kcp-dev/multicluster-provider v0.0.0-20250827085327-2b5ca378b7b4 h1:GUihV22j2J/cGF5Svr/zGVvfqTJepIO+sOnYTn9o4Vc=