additionalTrustBundle IsCA check to warn instead of drop

When using `additionalTrustBundle` accept v1 certificates and non-CA
certificates. In place of the drop warn user that the
certificate provided is either v1 or a non-CA certificate.

pkg/asset/manifests/additionaltrustbundleconfig.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/ghodss/yaml"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -114,10 +115,16 @@ func parseCertificates(certificates string) (map[string]string, error) {
 			return nil, err
 		}
 
-		if cert.IsCA {
-			sb.WriteString(string(pem.EncodeToMemory(block)))
+		if cert.Version < 3 {
+			logrus.Warnf("Certificate %X from additionalTrustBundle is x509 v%d", cert.SerialNumber, cert.Version)
+		} else {
+			if !cert.IsCA {
+				logrus.Warnf("Certificate %X from additionalTrustBundle is x509 v%d but not a certificate authority", cert.SerialNumber, cert.Version)
+			}
 		}
 
+		sb.WriteString(string(pem.EncodeToMemory(block)))
+
 		if len(rest) == 0 {
 			break
 		}