var headers map[string]string
headers["X-Yolo-Header"] = "Yolo-Value"       # <-- set a custom header in headers var
cfg := &genapi.TransportConfig{
		Schemes:  []string{gURL.Scheme},
		BasePath: "/api",
		Host:     gURL.Host,
		// APIKey is an optional API key or service account token.
		APIKey: credentials.apikey,
		// NumRetries contains the optional number of attempted retries
		NumRetries: 0,
		Client:     client,
		TLSConfig:  tlsConfig,
		HTTPHeaders: headers,         # <-- pass the headers as part of the TransportConfig to build and configure the returned *genapi.GrafanaHTTPAPI
	}

apiVersion: grafana.integreatly.org/v1beta1
kind: Grafana
metadata:
  labels:
    grafana-instance: grafana-kind-localhost
  name: grafana-kind-localhost
spec:
  client:
    headers:
       "X-Titi-Header": "toto"
       X-Yolo-Header: "Yolo-Value"
       x-grafana-org-id: "18"
  external:
    adminPassword:
      key: GF_SECURITY_ADMIN_PASSWORD
      name: grafana-kind-localhost-secrets
    adminUser:
      key: GF_SECURITY_ADMIN_USER
      name: grafana-kind-localhost-secrets
    url: https://grafana.kind.localhost