Layout.js

const Layout = ({ children }) => {
  useEffect(() => {
    // set version
    window.APP_VERSION = process.env.NEXT_PUBLIC_APP_VERSION;
  }, []);
  
}

export default Layout;

// now we can check at console APP_VERSION 

package.json

{
  "scripts": {
    "dev": "export NEXT_PUBLIC_APP_VERSION=$(git rev-parse HEAD) && next dev",
    "build": "next build",
    "export": "export NEXT_PUBLIC_APP_VERSION=$(git rev-parse HEAD) && next build && next export",
    "start": "next start",
    "lint": "next lint"
  },
}