gatsby-plugin-terminal-notifier

yarn add -D gatsby-plugin-terminal-notifier
# or
npm i -D gatsby-plugin-terminal-notifier

// gatsby-config.js
module.exports = {
  plugins: ['gatsby-plugin-terminal-notifier']
}

// gatsby-config.js
module.exports = {
  plugins: [
    {
      resolve: 'gatsby-plugin-terminal-notifier'
      options: {
        devNote: 'My custom dev notification',
        buildNote: 'My cool post build notification'
      }
    }
  ]
}