MySQL 8.0 Requested authentication method unknown to the client (caching_sha2_password)
You may check Upgrading to MySQL 8.0 : Default Authentication Plugin Considerations to get information about important notes on upgrading to 8.0 where you will find:
At the time of writing this post, following connectors do not have support for caching_sha2_password.
- PHP mysqli connector
- GO mysql connector
- PERL DBD-mysql connector
If you want to know more, you may check caching_sha2_password as the Preferred Authentication Plugin on MySQL official documentation.
So, I think that's soon to upgrade to MySQL 8.0 and you may consider downgrade or wait some time for php mysql extension to be upgraded as well.
I think you are using MySQL 8, the default method of authentication has changed, maybe you will need to change something in your server configuration.
Look this link: https://github.com/laradock/laradock/issues/1392#issuecomment-368308494
Another thing you can do is downgrade your MySQL version.