DsnParser doesn't map scheme like before

[Witold Wasiczko]

In doctrine dbal 3, I had url starts with: mysql:// and doctrine correctly handle this connection string. But now, even with #124 I still cannot make a connection (pdo-mysql is correct right now).

Looks like missing predefined scheme mapping in DsnParser https://github.com/Roave/psr-container-doctrine/pull/124/files#diff-a0906b5aa460579706c33a67d2bed0b0b2085cf46ef55a7d7ba103cbe5cf4407R116

It will be nice to be able to confiure this map. I see two ways:

1. Define map in config and pass to constructor.
2. Get DsnParser from container and then I be able to make map by my own.