Add TutorialSearch to Courses

[ParishKhan]

Hi! This PR adds TutorialSearch to the Courses section.

What is TutorialSearch?

TutorialSearch is a free, cross-platform search engine that indexes 50,000+ tutorials and courses from major learning platforms (Udemy, Skillshare, Pluralsight, and more) across 45+ categories — including programming, web development, AI/ML, cybersecurity, design, and more. No signup required.

It helps learners compare tutorials side-by-side by rating, price, and reviews before committing to a course, which I think makes it a useful addition to this list.

Entry added

- [TutorialSearch](https://tutorialsearch.io/browse/cybersecurity/reliability-engineering) - Free cross-platform search engine indexing 50,000+ tutorials from Udemy, Skillshare, Pluralsight, and other major learning platforms across 45+ categories.

Inserted in alphabetical order within the section. Happy to adjust formatting, description length, or placement if you'd like — just let me know!

Thanks for maintaining this list.

[mxssl]

Thanks for the contribution. I’m going to close this because the added links appear to be self-promotional, and we’re trying to keep the guide focused on broadly vetted SRE interview preparation resources.