remove npm cache
remove npm cache

It’s causing the tests to fail because there’s an old version of
create-torrent being used.

joshterrill/webtorrent,whitef0x0/webtorrent,rom1504/webtorrent,yciabaud/webtorrent,feross/webtorrent,Stiveknx/webtorrent,joshterrill/webtorrent,arestov/webtorrent,yciabaud/webtorrent,webtorrent/webtorrent,webtorrent/webtorrent,feross/webtorrent,whitef0x0/webtorrent,jamesliu96/webtorrent,jamesliu96/webtorrent,Stiveknx/webtorrent