message: Fix value for preserveMissingSpecs when using --only.
diff: @@ -41,7 +41,7 @@ export default async function getOptions({ argv, env, flags, log, packageJson })
  exitZeroOnChanges: flags.exitZeroOnChanges === '' ? true : flags.exitZeroOnChanges,
  exitOnceUploaded: flags.exitOnceUploaded === '' ? true : flags.exitOnceUploaded,
  ignoreLastBuildOnBranch: flags.ignoreLastBuildOnBranch,
  - preserveMissingSpecs: flags.preserveMissing || flags.only,
  + preserveMissingSpecs: flags.preserveMissing || !!flags.only,
  originalArgv: argv,
  buildScriptName: flags.buildScriptName,
  