add missing arguments for release:create command

This PR fix #110

I try to create this using gush programm but I always have the same error : 
```
 [Github\Exception\ValidationFailedException]                                                                                                                                                                                                
  Validation Failed: Field "head_sha" is missing, for resource "PullRequest", Field "base_sha" is missing, for resource "PullRequest", No commits between cordoval:110-missing-repo-and-org-arguments and lunika:110-missing-repo-and-org-ar  
  guments  
```

Maybe it's not possible to create a PR from a fork ?

Thx