TLSRoute: Require hostnames via +required (#3918)

* TLSRoute: Require hostnames, no omitempty

* TLSRoute: Require hostnames using +required

Author: rostislavbobo

apis/v1alpha3/tlsroute_types.go

@@ -86,6 +86,7 @@ type TLSRouteSpec struct {
 	//
 	// +kubebuilder:validation:MinItems=1
 	// +kubebuilder:validation:MaxItems=16
+	// +required
 	Hostnames []Hostname `json:"hostnames,omitempty"`
 
 	// Rules are a list of TLS matchers and actions.