change the version of `symfony/dependency-injection` to `~2.6,>=2.6.5` #5
change the version of `symfony/dependency-injection` to `~2.6,>=2.6.5` #5

This changes will avoid `ContextErrorException` as the following:

Warning: DOMElement::setAttribute() expects parameter 2 to be string, object given

For more information, see https://github.com/symfony/symfony/issues/13913.

phpmentors-jp/pageflower-bundle,phpmentors-jp/pageflower-bundle