small improvements (#958)

* small improvements

* fix: return empty iterator if no json present

* use time.Tick

* changes

pkg/ddns/webhook/webhook.go

@@ -77,7 +77,7 @@ func (provider *Provider) prepareRequest(ctx context.Context) (*http.Request, er
 		return nil, err
 	}
 
-	headers, err := utils.GjsonParseStringMap(
+	headers, err := utils.GjsonIter(
 		provider.formatWebhookString(provider.DDNSProfile.WebhookHeaders))
 	if err != nil {
 		return nil, err
@@ -139,7 +139,7 @@ func (provider *Provider) reqBody() (string, error) {
 	case requestTypeJSON:
 		return provider.formatWebhookString(provider.DDNSProfile.WebhookRequestBody), nil
 	case requestTypeForm:
-		data, err := utils.GjsonParseStringMap(provider.DDNSProfile.WebhookRequestBody)
+		data, err := utils.GjsonIter(provider.DDNSProfile.WebhookRequestBody)
 		if err != nil {
 			return "", err
 		}