Stop relying on the master version of Psalm

Mark every exception as immutable

I just got bitten by a bug on master at
https://github.com/doctrine/sql-formatter/pull/43#issuecomment-615576443,
and there are good chances we have the bug on the Dbal too. Anyway, it
only makes sense to use the same version as in the vendors.

Reworked LoggingTest to be able to test Statement::executeUpdate()

Remove baseline

null contradicts the phpdoc

For some reason a low version crashes Psalm.

Setup static analysis with Psalm

This should make it easier to work with Composer from machines using
different versions of PHP than the lowest one we use in the CI.

Manually merge 3.0.x into master

Make table and column comments non-nullable strings

Dropped support of fetching objects and non-zero column

1. `FetchMode::STANDARD_OBJECT` and `FetchMode::CUSTOM_OBJECT` are no longer supported.
2. `FetchMode::COLUMN` with a non-zero index is no longer supported.
3. Incompatible change in the `Connection::fetchColumn()` signature where the 3rd argument is now `$types`, not `$columnIndex`.

Upgrade PHPUnit to 9.1

Do not require hostname for non-persistent MySQL connection and require for persistent

Enable PHPStan strict rules