Merge branch '3.4' into 4.0

* 3.4:
  [Translation] Use unix-style EOL for xliff-core-1.2-strict.xsd
  bumped Symfony version to 3.4.9
  updated VERSION for 3.4.8
  updated CHANGELOG for 3.4.8
  bumped Symfony version to 2.8.39
  updated VERSION for 2.8.38
  updated CHANGELOG for 2.8.38
  bumped Symfony version to 2.7.46
  updated VERSION for 2.7.45
  update CONTRIBUTORS for 2.7.45
  updated CHANGELOG for 2.7.45
  [Yaml] Throw parse error on unfinished inline map

Author: xabbuh