chore: fix case typo

[cncolder]

What kind of change does this PR introduce?

fix typo

Did you add tests for your changes?

no need

Does this PR introduce a breaking change?

no

What needs to be documented once your changes are merged?

nothing

[jsf-clabot]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

[webpack-bot]

For maintainers only:

• This needs to be documented (issue in webpack/webpack.js.org will be filed when merged)
• This needs to be backported to webpack 4 (issue will be created when merged)

[webpack-bot]

Thank you for your pull request! The most important CI builds succeeded, we’ll review the pull request soon.

[sokra]

Could you sign the CLA?

[webpack-bot]

@cncolder Thanks for your update.

I labeled the Pull Request so reviewers will review it again.

@sokra Please review the new changes.

[cncolder]

Could you sign the CLA?

CLA signed and rebase.

[sokra]

Thanks