Feature request: make execution optional

[jmthibault79]

If this configuration setting exists, my apologies. I wasn't able to find it.

I really like the idea of this plugin and it has already shown us some interesting stats (we've got some lib-decades to address!) However I am planning to remove it from our project, because it significantly increases the build time for some of my team members. What I would like to do is to run this check conditionally, either using a flag or a separate command, rather than always running.

Would this be difficult to add?