title: Heroku throws "Incorrect or missing password." error when trying to install. Not happening locally
body: <p>I have a private GitHub package dependency that's registered through npm.
  <a href="https://docs.github.com/en/packages/working-with-a-github-packages-registry/working-with-the-npm-registry" rel="nofollow noreferrer">https://docs.github.com/en/packages/working-with-a-github-packages-registry/working-with-the-npm-registry</a></p>
  <p>Installing and building locally works but Heroku throws the following error:</p>
  <pre><code>   npm ERR! code E401
     npm ERR! Incorrect or missing password.
     npm ERR! If you were trying to login, change your password, create an
     npm ERR! authentication token or enable two-factor authentication then
     npm ERR! that means you likely typed your password in incorrectly.
     npm ERR! Please try again, or recover your password at:
     npm ERR!     https://www.npmjs.com/forgot
     npm ERR! 
     npm ERR! If you were doing some other operation then your saved credentials are
     npm ERR! probably out of date. To correct this please try logging in again with:
     npm ERR!     npm login
  </code></pre>
  <p>I've added an .npmrc with auth token as a Config Var but still no luck. Any suggestions?!</p>