Improve `exist` validator to support array attributes
Refactoring
Refactoring
Tests updated
Tests updated
MigrateCommand enhancement. `all` option added for `down` action.
CHANGELOG updated
Comments updated
Tests updated
ExistValidator count logic fix
CHANGELOG
CHANGELOG fixed
Fixed the issue that `ServiceLocator` still returns the old component after calling `set()` with a new definition
allow using errorhandler from the app namespace

fixes #3431
added ErrorHandler::deRegister()
changelog
typo
improved docs for AR::findAll()
allow non-lowercase package names

fixes #3438
updated the lifecycle chart. [skip ci]