Note: This command is unaware of workspaces.
Spawn a subshell in the directory of the installed package specified.
If a command is specified, then it is run in the subshell, which then
immediately terminates.
This is particularly handy in the case of git submodules in the
node_modules folder:
npm explore some-dependency -- git pull origin master
Note that the package is not automatically rebuilt afterwards, so be
sure to use npm rebuild <pkg> if you make any changes.