Support both PHP-DI 5.4.3+ and 6.x

Author: WyriHaximus

composer.json

@@ -14,7 +14,7 @@
     "api-clients/hydrator": "^1.0.1",
     "api-clients/middleware": "^4.0 || ^3.0 || ^2.0 || ^1.1",
     "api-clients/transport": "^3.0 || ^2.0 || ^1.0",
-    "php-di/php-di": "^5.4.3",
+    "php-di/php-di": "^6.0 || ^5.4.3",
     "psr/container": "^1.0"
   },
   "require-dev": {

composer.lock

@@ -54,12 +54,21 @@ public function handle($command)
         $this->assertSame($command, await($client->handle($command), $loop));
     }
 
-    /**
-     * @expectedException \DI\Definition\Exception\DefinitionException
-     */
     public function testCommandBusMissing()
     {
-        new Client(ContainerBuilder::buildDevContainer());
+        try {
+            new Client(ContainerBuilder::buildDevContainer());
+        } catch (\DI\Definition\Exception\InvalidDefinition $exception) {
+            self::assertTrue(true);
+
+            return;
+        } catch (\DI\Definition\Exception\DefinitionException $exception) {
+            self::assertTrue(true);
+
+            return;
+        }
+
+        self::assertTrue(false);
     }
 
     public function testHydrate()