Add auth support (#21)

* Updates

* Update

* Update

* Update

* Update

* Yarn sometimes prefers npmrc, so use same token

* Description

* Update readme

* Feedback

* Add type

* new toolkit and scoped registries

* npmrc in RUNNER_TEMP

* Dont always auth

* Try exporting blank token

* Get auth working for now pending runner changes

* Fix string interpolation for auth token.

* Don't export both userconfigs

* Update authutil.js

* Add single quotes for authString

* Fix the registry string.

* Use userconfig and append trailing slash

* Keep in root of repo

* Try just adding auth token

* Remove auth token

* Try changes again

* Add tests

* Npm and GPR samples

* Add types

node_modules/universal-user-agent/test/smoke-test.js

@@ -0,0 +1,57 @@
+// make tests run in both Node & Express
+if (!global.cy) {
+  const chai = require('chai')
+  const sinon = require('sinon')
+  const sinonChai = require('sinon-chai')
+  chai.use(sinonChai)
+  global.expect = chai.expect
+
+  let sandbox
+  beforeEach(() => {
+    sandbox = sinon.createSandbox()
+    global.cy = {
+      stub: function () {
+        return sandbox.stub.apply(sandbox, arguments)
+      },
+      log () {
+        console.log.apply(console, arguments)
+      }
+    }
+  })
+
+  afterEach(() => {
+    sandbox.restore()
+  })
+}
+
+const getUserAgent = require('..')
+
+describe('smoke', () => {
+  it('works', () => {
+    expect(getUserAgent()).to.be.a('string')
+    expect(getUserAgent().length).to.be.above(10)
+  })
+
+  if (!process.browser) { // test on node only
+    const proxyquire = require('proxyquire').noCallThru()
+    it('works around wmic error on Windows (#5)', () => {
+      const getUserAgent = proxyquire('..', {
+        'os-name': () => {
+          throw new Error('Command failed: wmic os get Caption')
+        }
+      })
+
+      expect(getUserAgent()).to.equal('Windows <version undetectable>')
+    })
+
+    it('does not swallow unexpected errors', () => {
+      const getUserAgent = proxyquire('..', {
+        'os-name': () => {
+          throw new Error('oops')
+        }
+      })
+
+      expect(getUserAgent).to.throw('oops')
+    })
+  }
+})