updated VERSION for 2.2.1
Merge branch 'v2.2.1' into 2.2

* v2.2.1:
  updated VERSION for 2.2.1
  Added '@@' escaping strategy for YamlFileLoader and YamlDumper
  [Yaml] fixed bugs with folded scalar parsing
  [FrameworkBundle] changed temp kernel name in cache:clear
  fixed id case when setting a service (also slightly enhanced an error message)
  remove dead code in yaml component
  Unset loading[$id] in ContainerBuilder on exception
  [Console] fixed StringInput binding
  [Console] added deprecation annotation
  [console] added string input test