Update the "suggest" section on composer.json

Eugene Leonovich · Eugene Leonovich · commit 4957fea66e3e · 2017-07-19T15:19:29.000+02:00
diff --git a/composer.json b/composer.json
@@ -28,6 +28,7 @@
         "symfony/process": "^3.2"
     },
     "suggest": {
+        "psr/container": "For using CallbackExecutor\\ContainerCallbackResolver.",
         "rybakit/arguments-resolver": "For using CallbackExecutor.",
         "symfony/process": "For using ProcessExecutor."
     },
