src\service\Google_Utils.php on line 58

 This video solution 

https://www.midrub.com/articles/array-and-string-offset-access-syntax-with-curly-braces-is-deprecated

or you can watch in youtube but same can resolve the problem

https://www.youtube.com/watch?v=OTdHuzXdTlQ&t=44s

The Conclusion is just change {} to []