deps: Upgrade to dbal v3

[aszenz]

Upgraded the package to use dbal v3

It will be a breaking change and require releasing a new major version.

My overall goal is to make https://github.com/thecodingmachine/tdbm work on dbal 3.

[aszenz]

@moufmouf Once this is merged I could work on making https://github.com/thecodingmachine/tdbm-fluid-schema-builder work with dbal 3

[moufmouf]

Absolutely excellent!

Technically, I think I could tag only a minor since the API of the library itself is not changing.

Composer should take care of the dependencies and as long as someone is not relying on the DBAL transitive dependency (which can be detected with https://github.com/maglnet/ComposerRequireChecker) and is correctly also adding DBAL in the require if they are using DBAL directly, we should be good.

[moufmouf]

Wait, I'm wrong, I need to tag a major because of $column->getDbalColumn() that exposes the DBAL type (that changed) to the outer world. Let's tag a 2.0!