Add cache:tag:invalidate command.

[cburschka]

This is a command for accessing Drupal's cache tag invalidator, which allows clearing caches more specifically than complete deletion, if you know what tags a cache entry is dependent on.

For example, when you're debugging a view, you can invalidate all related cache entries with drupal cache:tag:invalidate config:views.view.frontpage without having to actually trigger the view's save operation.

[jmolivas]

@cburschka Thanks for your contribution, your PR was merged. This will be included on the next release.