import buffalo when generating a new action

[lumost]

The current action generator does not import buffalo, and the resultant actions will fail to compile. This PR adds a quick fix and test.

[paganotoni]

this looks good to me, the actions generator runs Fmt task, which check on your system for the goimports package if you have it installed it will add the import, i think is better to add it by default and not relay on the goimports installation. thanks for this @lumost!

[markbates]

Thanks!