[Doctrine] Rules to upgrade DBAL from 2 to 3

[simivar]

Feature Request

doctrine/dbal of version 3 was released. It would be nice to have rectors to migrate from version 2 to 3. Upgrade list is available here. As there are many breaking changes it would be nice to prepare some specific issues and break them down into specific rules under one set.

[TomasVotruba]

There has been done some work already: #4517

See set: /~https://github.com/rectorphp/rector/blob/master/config/set/doctrine-dbal-30.php

We currently don't have any project with Dbal that we upgrade, so we'll not handle it.

Still, extending set is welcomed 👍