[2.7][BC Break][Assets] version argument in twig asset() function is broken

I couldn't find any related upgrade notes on this one. Any suggestions on how to continue here?

``` twig
{{ asset('/bundles/mybundle/js/webshop.js', version=md5_timestamp) }}
```

This gives me the following error: 

```
An exception has been thrown during the rendering of a template ("Property Symfony\Component\Asset\PathPackage::$versionStrategy does not exist")
```
