docs: fix reference to CHECKS file location
docs: fix reference to CHECKS file location

Closes #3664

claytonbrown/dokku,jimjag/dokku,claytonbrown/dokku,progrium/dokku,dokku/dokku,progrium/dokku,dokku/dokku,progrium/dokku,claytonbrown/dokku,progrium/dokku,jimjag/dokku,progrium/dokku,dokku/dokku,jimjag/dokku,progrium/dokku,claytonbrown/dokku,progrium/dokku,progrium/dokku,claytonbrown/dokku,dokku/dokku,jimjag/dokku,claytonbrown/dokku,claytonbrown/dokku,jimjag/dokku,dokku/dokku,dokku/dokku,jimjag/dokku,jimjag/dokku,claytonbrown/dokku,dokku/dokku,jimjag/dokku,dokku/dokku