Merge pull request #37 from jtpio/npm-pack-output

Use the last line of the `npm pack` command

Author: Steven Silvester

jupyter_releaser/npm.py

@@ -24,7 +24,7 @@ def build_dist(package, dist_dir):
 
     if osp.isdir(package):
         basedir = package
-        tarball = osp.join(package, util.run("npm pack", cwd=package))
+        tarball = osp.join(package, util.run("npm pack", cwd=package).split("\n")[-1])
     else:
         basedir = osp.dirname(package)
         tarball = package