try yarn.cmd explicitly

Timer · Timer · commit 1332a190edac · 2017-11-19T15:04:31.000-05:00
diff --git a/packages/react-scripts/scripts/eject.js b/packages/react-scripts/scripts/eject.js
@@ -48,7 +48,7 @@ function adjustPackages(cwd, packages, append, dev) {
   let status, output;
   if (fs.existsSync(paths.yarnLockFile)) {
     ({ status, output } = spawnSync(
-      process.platform === 'win32' ? 'yarnpkg.cmd' : 'yarnpkg',
+      process.platform === 'win32' ? 'yarn.cmd' : 'yarnpkg',
       [append ? 'add' : 'remove', ...packages],
       {
         stdio: 'pipe',

Original file line number	Diff line number	Diff line change
`@@ -48,7 +48,7 @@ function adjustPackages(cwd, packages, append, dev) {`
`48`	`48`	`let status, output;`
`49`	`49`	`if (fs.existsSync(paths.yarnLockFile)) {`
`50`	`50`	`({ status, output } = spawnSync(`
`51`		`- process.platform === 'win32' ? 'yarnpkg.cmd' : 'yarnpkg',`
	`51`	`+ process.platform === 'win32' ? 'yarn.cmd' : 'yarnpkg',`
`52`	`52`	`[append ? 'add' : 'remove', ...packages],`
`53`	`53`	`{`
`54`	`54`	`stdio: 'pipe',`