title: npm update is not updating the version in package.json file
body: <p>I am trying to update specific package in my project. I have checked it using <code>npm outdated</code> and then I run this command to update this package: <code>npm update nameofpackage</code> i.e., <code>npm update slugify</code>.</p>
  <p>My package.json file is not got updated after that, although when i run npm outdated again it shows no outdated package. It means it got updated but my package.json file still shows the older version of the package.</p>
  <p>Please let me know how can I update my package.json file also. I have tried <code>npm update slugify --save</code> also but it didn't worked for me.</p>