build-storybook ignores -o output option

[Jakobud]

Describe the bug
According to the documentation (https://storybook.js.org/docs/html/workflows/publish-storybook) I should be able to specify the output directory when publishing storybook to static files:

$ npm run build-storybook -o ./path/to/output

But when I do this, it ignores the -o and outputs to ./storybook-static directory every time.

Expected behavior
It outputs static files to the specified directory.

System
Please paste the results of npx sb@next info here.

    OS: Windows 10 10.0.18363
    CPU: (16) x64 AMD Ryzen 7 3700X 8-Core Processor
  Binaries:
    Node: 14.15.4 - C:\Program Files\nodejs\node.EXE
    npm: 6.14.10 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Spartan (44.18362.449.0)
  npmPackages:
    @storybook/addon-actions: ^6.1.14 => 6.1.14
    @storybook/addon-essentials: ^6.1.14 => 6.1.14
    @storybook/addon-links: ^6.1.14 => 6.1.14
    @storybook/html: ^6.1.14 => 6.1.14

[jeffreymoelands]

#10570

[gaetanmaisse]

Closing as a duplicate of #10570