Integration in Symfony 5 is not possible because of css selector version in composer.json

[romainst]

Steps required to reproduce the problem

1. Integration of the SDK is not possible within Symfony 5 because of symfony/css-selector versions stated in composer.json

Expected Result

• Building works properly without Symfony 4 files

Actual Result

• Building with Symfony 5 does not work

Suggested fix in composer.json

"symfony/css-selector": "^2.8 || ^3.1 || ^4.1 || ^5.1",

[victorbuild]

Hi! how do you deal with this problem?