If you are runing wordpress on any VPS like DigitalOcean. Having site folder with incorrect set of permissions could show following message upon updating wordpress or plugin.
To perform the requested action, WordPress needs to access your web server. Please enter your FTP credentials to proceed. If you do not remember your credentials, you should contact your web host.
This issue can be resolve by running following command:
sudo chown -Rf www-data:www-data /var/www/wordpress