Allow php 8

Deprecated the concept of the fetch mode

Deprecated Connection::project(), Statement::errorCode() and errorInfo()

This makes it consistent with doctrine-bundle command

Fix character for mysql driver example

Coveralls integration

Remove useless rules

For UTF-8: SQLSTATE[HY000] [2019] Unknown character set

allow using multiple connections for CLI commands

Fix logging in functional tests in case of connection failure

Extend RetryableException from Throwable interface

Let RetryableException extend from the Throwable interface to prevent errors in Psalm if catching it

We are calling them in uppercase since 64939c35

This exclude rule is here because of a false positive that has been
fixed since slevomat/coding-standard 6.1.2

Use proper check in acceptForeignKey()

move PHPStan to GitHub Actions

Checking that the platform supports foreign key is not the right case
here, because we should check if we can create them by themselves, after
the table is created. It is not the case for Sqlite.

Closes #3990

Move phpcs from Travis to GitHub Actions