migration symfony 5 4 (#300)

* symfony 5.4 (diff dev)

* symfony 5.4 (working)

* symfony 5.4 (update autoload)

* symfony 5.4 (remove swiftmailer mailer implementation)

* symfony 5.4 (php doc and split Global accessor class)


### Impacted packages:

composer require php:">=7.2.5 <8.0.0" symfony/console:5.4.* symfony/dotenv:5.4.* symfony/framework-bundle:5.4.* symfony/twig-bundle:5.4.* symfony/yaml:5.4.* --update-with-dependencies

composer require symfony/stopwatch:5.4.* symfony/web-profiler-bundle:5.4.* --dev --update-with-dependencies

lib/symfony/config/ConfigCacheInterface.php

@@ -23,7 +23,7 @@ interface ConfigCacheInterface
     /**
      * Gets the cache file path.
      *
-     * @return string The cache file path
+     * @return string
      */
     public function getPath();
 
@@ -32,7 +32,7 @@ interface ConfigCacheInterface
      *
      * This check should take the metadata passed to the write() method into consideration.
      *
-     * @return bool Whether the cache is still fresh
+     * @return bool
      */
     public function isFresh();
 
@@ -45,5 +45,5 @@ interface ConfigCacheInterface
      *
      * @throws \RuntimeException When the cache file cannot be written
      */
-    public function write($content, array $metadata = null);
+    public function write(string $content, array $metadata = null);
 }