docs: update discussion link in README

Author: FidelusAleksander

README.md

@@ -55,6 +55,6 @@ In this exercise, you will:
 
 ---
 
-Get help: [Post in our discussion board](https://github.com/orgs/skills/discussions/categories/introduction-to-github) • [Review the GitHub status page](https://www.githubstatus.com/)
+Get help: [Post in our discussion board](https://github.com/orgs/skills/discussions/categories/getting-started-with-github-copilot) • [Review the GitHub status page](https://www.githubstatus.com/)
 
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