Fix: Add missing comma in array initialization

A missing `,` in `config/development.local.php.dist` results in the following error

```
Parse error: syntax error, unexpected ''service_manager'' (T_CONSTANT_ENCAPSED_STRING), expecting ']' in /Users/am/Sites/zendframework/modules.zendframework.com/config/autoload/development.local.php on line 7
```

when switching the application into development mode via

```
$ php public/index.php development enable
```