Merge branch '3.4' into 4.2

* 3.4:
  bumped Symfony version to 3.4.26
  updated VERSION for 3.4.25
  update CONTRIBUTORS for 3.4.25
  updated CHANGELOG for 3.4.25
  Workaround for \DateInterval::createFromDateString()
  Missing Lithuanian translations added to validator component.

Author: nicolas-grekas