Update README for 7.5

[sdwheeler]

PR Summary

Add reference to PowerShell 7.5 folder in the README file.

PR Checklist

• Descriptive Title: This PR's title is a synopsis of the changes it proposes.
• Summary: This PR's summary describes the scope and intent of the change.
• Contributor's Guide: I have read the contributors guide.
• Style: This PR adheres to the style guide.

[learn-build-service-prod]

Learn Build status updates of commit ccc8023:

✅ Validation status: passed

File	Status	Preview URL	Details
README.md	✅Succeeded

For more details, please refer to the build report.

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