Allow unrestricted updates to .github/skills folder (#9666)

advised by @timotheeguerin 
<img width="1197" height="212" alt="image"
src="https://github.com/user-attachments/assets/0a06d165-58f1-4060-b5e3-90e96b600ca4"
/>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: msyyc <70930885+msyyc@users.noreply.github.com>
Co-authored-by: Yuchao Yan <yuchaoyan@microsoft.com>

Author: Copilot

.github/CODEOWNERS

@@ -3,6 +3,7 @@
 
 # Those files/folders can be modified by anyone
 .chronus/changes/
+.github/skills/
 cspell.yaml
 
 ######################