Fix default `emptyDirFilter`

[s100]

It looks as if you copied and pasted the default emptyDirFilter from empty-dir's own documentation, which (at the time) was broken. A completely understandable error. I have opened a PR to fix empty-dir's documentation, but this usage must also be repaired. With its current behaviour, modclean considers nearly every directory to be empty and deletable by default, except those containing only garbage files.

[s100]

Incidentally, is modclean@3 intended to be ready for production use? If not, I highly recommend you mark [email protected] as latest on npm.