Merge branch '6.4' into 7.0

* 6.4:
  fix typo
  remove the WriteConfig class
  DX: PHP CS Fixer - keep Annotation,NamedArgumentConstructor,Target annotations as single group
  do not install FrameworkBundle 6.4
  [Tests] Add `array` return type for provider methods
  [Tests] Move expectException closer to the place of the expectation to avoid false positives

Tests/Extension/Core/DataTransformer/DateTimeToRfc3339TransformerTest.php

@@ -43,12 +43,12 @@ public static function allProvider(): array
         ];
     }
 
-    public static function transformProvider()
+    public static function transformProvider(): array
     {
         return self::allProvider();
     }
 
-    public static function reverseTransformProvider()
+    public static function reverseTransformProvider(): array
     {
         return array_merge(self::allProvider(), [
             // format without seconds, as appears in some browsers
@@ -126,7 +126,7 @@ public function testReverseTransformExpectsValidDateString($date)
         $transformer->reverseTransform($date);
     }
 
-    public static function invalidDateStringProvider()
+    public static function invalidDateStringProvider(): array
     {
         return [
             'invalid month' => ['2010-2010-01'],