Fixes #16127 - Bumping up the foreman-tasks requirement

[daviddavis]

Per theforeman/foreman-packaging#1265 (comment), we need to bump the foreman-tasks requirement to support foreman-tasks 0.8.0. Let me know if you'd prefer that I use a different requirement like '>= 0.6.9', '< 0.9.0'.

[stbenjam]

In order to make a release we'll need to do strong params too, pr here : #49

[ares]

I think we don't have to be that strict, '>= 0.8' works for me fine, there are not that many incompatible changes in foreman-tasks from my experience

[daviddavis]

@ares done.

[ares]

Thank you @daviddavis, merging!