refactor #10829 Remove Symfony ^3.4 support on the master branch (pamil)
refactor #10829 Remove Symfony ^3.4 support on the master branch (pamil)

This PR was merged into the 1.7-dev branch.

Discussion
----------

Sylius 1.7 is about to be released in February 2020, we need to start getting rid of Symfony 4 deprecations. 

Symfony 4.4 LTS is about to be released at the end of this month, so Sylius will require it also.

Commits
-------

cd74879075caad5310a0252aca534bc87d8262a2 Deprecate Symfony ^3.4 on the master branch

Sylius/Attribute