How to generate a simple random password in PHP

As I often work with APIs for our clients, I often need a simple password generator that creates a random password using numbers and letters, both lowercase and uppercase. The function below is a simple example.

// Generate a simple random password
function getRandomPassword($length = 8){
  $data = '1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcefghijklmnopqrstuvwxyz';
  return substr(str_shuffle($data), 0, $length);