UPGRADE FROM 4.2 to 4.3
=======================
BrowserKit
----------
* Marked `Response` final.
* Deprecated `Response::buildHeader()`
* Deprecated `Response::getStatus()`, use `Response::getStatusCode()` instead
Config
------
* Deprecated using environment variables with `cannotBeEmpty()` if the value is validated with `validate()`
Form
----
* Using the `date_format`, `date_widget`, and `time_widget` options of the `DateTimeType` when the `widget` option is
set to `single_text` is deprecated.
FrameworkBundle
---------------
* Not passing the project directory to the constructor of the `AssetsInstallCommand` is deprecated. This argument will
be mandatory in 5.0.