[FrameworkBundle] composer suggest fix

| Q             | A
| ------------- | ---
| Bug fix?      | [yes]
| New feature?  | [yes|no]
| BC breaks?    | [yes|no]

Since cache is now required, it makes no sense to suggest it

src/Symfony/Bundle/FrameworkBundle/composer.json

@@ -55,8 +55,7 @@
         "symfony/form": "For using forms",
         "symfony/serializer": "For using the serializer service",
         "symfony/validator": "For using validation",
-        "symfony/yaml": "For using the debug:config and lint:yaml commands",
-        "doctrine/cache": "For using alternative cache drivers"
+        "symfony/yaml": "For using the debug:config and lint:yaml commands"
     },
     "autoload": {
         "psr-4": { "Symfony\\Bundle\\FrameworkBundle\\": "" }