In a Kubernetes Engine deployment, your engineers have hardcoded database credentials in the YAML configuration as shown below. What is Google's recommended best practice for handling sensitive information like this in Kubernetes?

apiVersion: "extensions/v1beta1"
kind: "Deployment"
metadata:
  name: "products-service"
  namespace: "default"
  labels:
    app: "products-service"
spec:
  replicas: 3
  selector:
    matchLabels:
      app: "products-service"
  template:
    metadata:
      labels:
        app: "products-service"
    spec:
      containers:
      - name: "products"
        image: "gcr.io/find-seller-app-dev/products:latest"
        env:
        - name: "database_user"
          value: "admin"
        - name: "database_password"
          value: "TheB3stP@ssW0rd"