Merge branch '5.0' into 5.1

* 5.0:
  Handle fetch mode deprecation of DBAL 2.11.
  Fixed handling of CSRF logout error
  [WebProfilerBundle] changed label of memory usage in time panel (Mb into MiB)
  [DotEnv][WebLink][Templating][ErrorHandler] Updated README with minimal example

Author: nicolas-grekas

README.md

@@ -3,6 +3,35 @@ ErrorHandler Component
 
 The ErrorHandler component provides tools to manage errors and ease debugging PHP code.
 
+Getting Started
+---------------
+
+```
+$ composer require symfony/error-handler
+```
+
+```php
+use Symfony\Component\ErrorHandler\Debug;
+use Symfony\Component\ErrorHandler\ErrorHandler;
+use Symfony\Component\ErrorHandler\DebugClassLoader;
+
+Debug::enable();
+
+// or enable only one feature
+//ErrorHandler::register();
+//DebugClassLoader::enable();
+
+$data = ErrorHandler::call(static function () use ($filename, $datetimeFormat) {
+    // if any code executed inside this anonymous function fails, a PHP exception
+    // will be thrown, even if the code uses the '@' PHP silence operator
+    $data = json_decode(file_get_contents($filename), true);
+    $data['read_at'] = date($datetimeFormat);
+    file_put_contents($filename, json_encode($data));
+
+    return $data;
+});
+```
+
 Resources
 ---------