Test shellcheck in CI

[mfialaf]

No description provided.

[CLAassistant]

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.

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Marek Fiala seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
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[github-actions]

	Warnings
⚠️	The PR description looks very brief, please check if more details can be added.
⚠️	Some issues found for the commit messages in this MR: the commit message Fix failing CI may not be sufficiently descriptive Please consider updating these commit messages.

	Messages
📖	You might consider squashing your 3 commits (simplifying branch history).

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👋 Welcome mfialaf, thank you for your first contribution to espressif/esp-idf project!

📘 Please check Contributions Guide for the contribution checklist, information regarding code and documentation style, testing and other topics.

🖊️ Please also make sure you have read and signed the Contributor License Agreement for espressif/esp-idf project.

Pull request review and merge process you can expect

Espressif develops the ESP-IDF project in an internal repository (Gitlab). We do welcome contributions in the form of bug reports, feature requests and pull requests via this public GitHub repository.

1. An internal issue has been created for the PR, we assign it to the relevant engineer
2. They review the PR and either approve it or ask you for changes or clarifications
3. Once the Github PR is approved, we synchronize it into our internal git repository
4. In the internal git repository we do the final review, collect approvals from core owners and make sure all the automated tests are passing
   • At this point we may do some adjustments to the proposed change, or extend it by adding tests or documentation.
5. If the change is approved and passes the tests it is merged into the master branch
6. On next sync from the internal git repository merged change will appear in this public Github repository

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_{🔁 You can re-run automatic PR checks by retrying the DangerJS action}

Generated by 🚫 dangerJS against 3e4cde6

[dobairoland]

@mfialaf I think this can be closed now, right?