Fix lint errors

components/cgu/cgu-dialog.js

@@ -1,8 +1,8 @@
-import React from 'react'
+import {useRef, useEffect} from 'react'
 import PropTypes from 'prop-types'
 import {Button, Dialog, DialogActions, DialogContent, DialogTitle, makeStyles, Typography} from '@material-ui/core'
-import Cgu from '.'
 import {useRouter} from 'next/router'
+import Cgu from '.'
 
 const CGU_DOWNLOAD_LINK = process.env.NEXT_PUBLIC_CGU_DOWNLOAD_LINK
 
@@ -25,8 +25,8 @@ export default function CGUDialog({open, setOpen}) {
     router.push(CGU_DOWNLOAD_LINK)
   }
 
-  const descriptionElementRef = React.useRef(null)
-  React.useEffect(() => {
+  const descriptionElementRef = useRef(null)
+  useEffect(() => {
     if (open) {
       const {current: descriptionElement} = descriptionElementRef
       if (descriptionElement !== null) {