title: apm update: error: unable to get local issuer certificate
body: <p>Recently, I tried re-installing vim-mode-plus on atom, and when that didn't work I decided to run <code>apm update</code> to ensure my package manager for atom was up to date. I am getting the error: </p>
  
  <p><code>Unable to download https://www.atom.io/api/packages/vim-mode-plus/versions/1.31.0/tarball: unable to get local issuer certificate
  </code></p>
  
  <p>I am assuming this has to do with my corporate proxy, how do I fix this?</p>