Update composer dependencies

Conflicts:
	composer.phar

composer.json

@@ -8,16 +8,20 @@
         {
             "type": "vcs",
             "url": "https://gitlab.version.fz-juelich.de/jards/GCSJARDSAPIClient.git"
+        },
+        {
+			"type" : "vcs",
+			"url" : "https://gitlab.version.fz-juelich.de/jards/Silex.git"
 		}
     ],
 	"require": {
-		"silex/silex": ">=2.0",
+		"silex/silex" : "^2.3",
 		"jards/eventsapiclient": "=3.2",
 		"jards/gcsjardsapiclient": "=2.1",
 		"phpmailer/phpmailer": ">=6.0"
 	},
 	"require-dev": {
-        "phpunit/phpunit": "^5.0"
+        "phpunit/phpunit": "^7.0"
     },
 	 "autoload": {
         "psr-4": {	"jards\\eventsapi\\": "lib/",