Update suggest package for robo.

[ghost]

Q	A
Branch	master
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	yes
Documented?	yes
Fixed tickets

Changing the suggestion for the robo package to reflect what is in the documentation (https://github.com/phpro/grumphp/blob/master/doc/tasks/robo.md#robo). The current package within the suggest section of the composer.json (https://packagist.org/packages/codegyre/robo) is abandoned. It needs to be changed to consolidation/robo.

[veewee]

Thanks!