npm prepublish changes

npm-help-scripts

PREPUBLISH AND PREPARE
   DEPRECATION NOTE
       Since  [email protected],  the npm CLI has run the prepublish script for both npm publish
       and npm install, because it's a convenient way to prepare a package for use  (some
       common  use  cases are described in the section below).  It has also turned out to
       be, in practice, very confusing  https://github.com/npm/npm/issues/10074.   As  of
       [email protected],  a new event has been introduced, prepare, that preserves this existing
       behavior. A new event, prepublishOnly has been added as a transitional strategy to
       allow  users to avoid the confusing behavior of existing npm versions and only run
       on npm publish (for instance, running the tests one last time to ensure they're in
       good shape).

       IMPORTANT:  As  of  npm@5, prepublish will only be run for npm publish.  This will
       make its behavior identical to prepublishOnly, so npm@6 or later may drop  support
       for  the use of prepublishOnly, and then maybe we can all forget this embarrassing
       thing ever happened.

       See https://github.com/npm/npm/issues/10074 for a  much  lengthier  justification,
       with further reading, for this change.