fix(owner): Fix the currently broken yarn owner command (#5593)

**Summary**

* fixing currently broken owner command
* doesn't ask for npm username and password for list command
* adding basic test #3893 

**Test plan**

Yarn now correctly displays the list of package owners. Also added automated tests.

__tests__/commands/__snapshots__/owner.js.snap

@@ -0,0 +1,8 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`list should show owners 1`] = `
+"{\\"type\\":\\"warning\\",\\"data\\":\\"package.json: No license field\\"}
+{\\"type\\":\\"step\\",\\"data\\":{\\"message\\":\\"Getting owners for package \\\\\\"yarn\\\\\\"\\",\\"current\\":1,\\"total\\":1}}
+{\\"type\\":\\"info\\",\\"data\\":\\"daniel15 <[email protected]>\\"}
+"
+`;

__tests__/commands/owner.js

@@ -0,0 +1,26 @@
+/* @flow */
+
+import {JSONReporter} from '../../src/reporters/index.js';
+import {run as buildRun} from './_helpers.js';
+import {run as owner} from '../../src/cli/commands/owner.js';
+
+const path = require('path');
+
+const fixturesLoc = path.join(__dirname, '..', 'fixtures', 'owner');
+
+const runOwner = buildRun.bind(
+  null,
+  JSONReporter,
+  fixturesLoc,
+  async (args, flags, config, reporter, lockfile, getStdout): Promise<string> => {
+    reporter.disableProgress();
+    await owner(config, reporter, flags, args);
+    return getStdout();
+  },
+);
+
+test('list should show owners', async (): Promise<void> => {
+  await runOwner(['list', 'yarn'], {nonInteractive: true}, '', (config, reporter, stdout) => {
+    expect(stdout).toMatchSnapshot();
+  });
+});

__tests__/fixtures/owner/package.json

@@ -0,0 +1,3 @@
+{
+    "name": "yarn"
+}

src/cli/commands/owner.js

@@ -87,14 +87,11 @@ async function list(config: Config, reporter: Reporter, flags: Object, args: Arr
   if (args.length > 1) {
     return false;
   }
-
   const name = await getName(args, config);
-
-  reporter.step(1, 3, reporter.lang('loggingIn'));
-  const revoke = await getToken(config, reporter, name);
-
-  reporter.step(2, 3, reporter.lang('ownerGetting', name));
-  const pkg = await config.registries.npm.request(name);
+  reporter.step(1, 1, reporter.lang('ownerGetting', name));
+  const pkg = await config.registries.npm.request(name, {
+    headers: {Accept: 'application/json'},
+  });
   if (pkg) {
     const owners = pkg.maintainers;
     if (!owners || !owners.length) {
@@ -108,9 +105,6 @@ async function list(config: Config, reporter: Reporter, flags: Object, args: Arr
     reporter.error(reporter.lang('ownerGettingFailed'));
   }
 
-  reporter.step(3, 3, reporter.lang('revokingToken'));
-  await revoke();
-
   if (pkg) {
     return true;
   } else {