Warnings when used with Rollup >= 1.27.0

[Lalem001]

1.27.0 added support for output-specific plugins Rollup#3218. This support also added a warning that appears as follows:

The "${hookName}" hook used by the output plugin ${pluginName} is a build time hook and will not be run for that plugin. Either this plugin cannot be used as an output plugin, or it should have an option to configure it as an output plugin.

I bring this up here because a config that is ok to use in rollup directly, end up spamming the terminal with these errors when used with karma-rollup-preprocessor.

I would make an example config, but its visible in the tests within this repo already.