Fix v1.3.0 release URL in README.md (#3782)

Author: szviagintsev

README.md

@@ -71,7 +71,7 @@ Participation in the Kubernetes community is governed by the
 [spec]: https://gateway-api.sigs.k8s.io/reference/spec/
 [concepts]: https://gateway-api.sigs.k8s.io/concepts/api-overview
 [security-model]: https://gateway-api.sigs.k8s.io/concepts/security-model
-[gh_release]: https://github.com/kubernetes-sigs/gateway-api/releases/tag/v1.2.1
+[gh_release]: https://github.com/kubernetes-sigs/gateway-api/releases/tag/v1.3.0
 [godoc]: https://pkg.go.dev/sigs.k8s.io/gateway-api
 [conformance-docs]: https://gateway-api.sigs.k8s.io/concepts/conformance/
 [reports-readme]: ./conformance/reports/README.md