Fix typo: "Mutiple" → "Multiple" in Object Tracker link

[JulianGStudium]

Description

Fixes a small spelling error in the README: "Mutiple" → "Multiple" in the "Multiple Object Tracker" link.

Motivation and Context

The linked article is about multi-object tracking, so "Multiple" is the correct spelling. This improves readability of the list.

How Has This Been Tested?

Text-only change. Verified the corrected spelling and confirmed the existing link still points to the same valid article.

Types of changes

• Content Update (change which fixes an issue or updates an already existing submission)
• New Article (change which adds functionality)
• Documentation change

Checklist:

• My code follows the code style of this project.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have made checks to ensure URLs and other resources are valid

#HSFDPMUW