Ping the version of the completion script to 0.6.1
Ping the version of the completion script to 0.6.1

The latest released version (0.7.0, and thus master) resulted the
following error being thrown whenever yarn completion is attemped:

``` text
"counter" and "cmd" must be set by the caller and be the appropriate type
```

Ref: https://github.com/dsifford/yarn-completion/blob/1126d4ccb8ff4c788d50d34dbcdefcb541cf3878/yarn-completion.bash#L133-L136

Unfortunately I don't have time to track this down so this revert will
have to do, for now.

marvinpinto/kitchensink,marvinpinto/kitchensink,marvinpinto/kitchensink