Allow individual bridges, bundles and components to be used with 4.0

Author: dunglas

composer.json

@@ -24,9 +24,9 @@
         "symfony/http-kernel": ""
     },
     "require-dev": {
-        "symfony/event-dispatcher": "^2.8|^3.0",
-        "symfony/http-foundation": "^2.8|^3.0",
-        "symfony/http-kernel": "^2.8|^3.0"
+        "symfony/event-dispatcher": "^2.8|^3.0|~4.0.0",
+        "symfony/http-foundation": "^2.8|^3.0|~4.0.0",
+        "symfony/http-kernel": "^2.8|^3.0|~4.0.0"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\WebLink\\": "" },