title: npm audit EINVALIDTAGNAME
body: <p>When I execute npm audit in a folder with the project's <code>package.json</code> and <code>package-lock.json</code> I get the following error:</p>
  
  <pre><code>0 info it worked if it ends with ok
  1 verbose cli [ '/home/user/Downloads/node-v10.14.0-linux-x64/bin/node',
  1 verbose cli   '/home/user/Downloads/node-v10.14.0-linux-x64/bin/npm',
  1 verbose cli   'audit' ]
  2 info using npm@6.5.0
  3 info using node@v10.14.0
  4 verbose npm-session d5b5c65bd8e7ae03
  5 verbose stack Error: Invalid tag name "[object Object]": Tags may not have any characters that encodeURIComponent encodes.
  5 verbose stack     at invalidTagName (/home/user/Downloads/node-v10.14.0-linux-x64/lib/node_modules/npm/node_modules/npm-package-arg/npa.js:87:15)
  5 verbose stack     at fromRegistry (/home/user/Downloads/node-v10.14.0-linux-x64/lib/node_modules/npm/node_modules/npm-package-arg/npa.js:290:13)
  5 verbose stack     at Function.resolve (/home/user/Downloads/node-v10.14.0-linux-x64/lib/node_modules/npm/node_modules/npm-package-arg/npa.js:77:12)
  5 verbose stack     at Object.keys.forEach.name (/home/user/Downloads/node-v10.14.0-linux-x64/lib/node_modules/npm/node_modules/lock-verify/index.js:26:26)
  5 verbose stack     at Array.forEach (&lt;anonymous&gt;)
  5 verbose stack     at Promise.all.then.result (/home/user/Downloads/node-v10.14.0-linux-x64/lib/node_modules/npm/node_modules/lock-verify/index.js:25:25)
  6 verbose cwd /home/user/projects/test-npm/CRYPTOSTORAGE/repos/crypto-storage/etc/approvalClient
  7 verbose Linux 3.10.0-862.14.4.el7.x86_64
  8 verbose argv "/home/user/Downloads/node-v10.14.0-linux-x64/bin/node" "/home/user/Downloads/node-v10.14.0-linux-x64/bin/npm" "audit"
  9 verbose node v10.14.0
  10 verbose npm  v6.5.0
  11 error code EINVALIDTAGNAME
  12 error Invalid tag name "[object Object]": Tags may not have any characters that encodeURIComponent encodes.
  13 verbose exit [ 1, true ]
  </code></pre>
  
  <p>If this would happen to only one project - but actually it does indeed happen to all projects that I've tried (~70). There is an internal registry, but I've both removed the local <code>.npmrc</code> and the one in home. Also the error I was getting then was a different one. </p>
  
  <p>Is this a bug or am I doing something wrong?</p>