fix(backend/kubernetes): Ensure valid naming of name field (#1661)

- Kubernetes v1.26 on VKE causes error when creating persistent volume
claim because of uppercase characters in name field

This patch is trivial just in order to get it working - happy to
implement differently.

The error in question:

```
The PersistentVolumeClaim "wp-01G1131R63FWBSPMA4ZAZTKLE-0-clone-0" is invalid: metadata.name: Invalid value: "wp-01G1131R63FWBSPMA4ZAZTKLE-0-clone-0": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')
```

pipeline/backend/kubernetes/utils.go

@@ -1,7 +1,9 @@
 package kubernetes
 
 import (
+	"errors"
 	"os"
+	"regexp"
 	"strings"
 
 	v1 "k8s.io/api/core/v1"
@@ -10,8 +12,19 @@ import (
 	"k8s.io/client-go/tools/clientcmd"
 )
 
-func dnsName(i string) string {
-	return strings.Replace(i, "_", "-", -1)
+var (
+	dnsPattern           = regexp.MustCompile(`^[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$`)
+	ErrDNSPatternInvalid = errors.New("name is not a valid kubernetes DNS name")
+)
+
+func dnsName(i string) (string, error) {
+	res := strings.Replace(i, "_", "-", -1)
+
+	if found := dnsPattern.FindStringIndex(res); found == nil {
+		return "", ErrDNSPatternInvalid
+	}
+
+	return res, nil
 }
 
 func isImagePullBackOffState(pod *v1.Pod) bool {