Merge pull request #5753 from alcohol/use-rfc3339-in-arraydumper

bring arraydumper in line with json schema spec and packagist

src/Composer/Package/Dumper/ArrayDumper.php

@@ -83,7 +83,7 @@ class ArrayDumper
         }
 
         if ($package->getReleaseDate()) {
-            $data['time'] = $package->getReleaseDate()->format('Y-m-d H:i:s');
+            $data['time'] = $package->getReleaseDate()->format(DATE_RFC3339);
         }
 
         $data = $this->dumpValues($package, $keys, $data);

tests/Composer/Test/Package/Dumper/ArrayDumperTest.php

@@ -104,9 +104,9 @@ class ArrayDumperTest extends \PHPUnit_Framework_TestCase
             ),
             array(
                 'time',
-                new \DateTime('2012-02-01'),
+                $datetime = new \DateTime('2012-02-01'),
                 'ReleaseDate',
-                '2012-02-01 00:00:00',
+                $datetime->format(DATE_RFC3339),
             ),
             array(
                 'authors',