fix(publishing-bumped-packages): look for status code instaead of stderr

Summary:
Changelog: [Internal]

This fixes CircleCI job, which is responsible for publishing bumped packages. We should not check for `stderr`, apparently `npm` uses it to store debug information:
- npm/npm#118 (comment)

So we've tried to use this on 0.71-stable before and it succesfully published one package, but have exited right after it because `stderr` was not empty

Differential Revision: D42836212

fbshipit-source-id: 8dfaa05c552589c9deac1a8184c14017d13bfdf3

scripts/monorepo/find-and-publish-all-bumped-packages.js

@@ -103,13 +103,13 @@ const findAndPublishAllBumpedPackages = () => {
 
       const npmOTPFlag = NPM_CONFIG_OTP ? `--otp ${NPM_CONFIG_OTP}` : '';
 
-      const {stderr} = spawnSync('npm', ['publish', `${npmOTPFlag}`], {
+      const {status} = spawnSync('npm', ['publish', `${npmOTPFlag}`], {
         cwd: packageAbsolutePath,
         shell: true,
         stdio: 'pipe',
         encoding: 'utf-8',
       });
-      if (stderr) {
+      if (status !== 0) {
         console.log(
           `\u274c Failed to publish version ${nextVersion} of ${packageManifest.name}:`,
         );