Update banner destination links to YOLO27

[raimbekovm]

Update the banner destination links to the YOLO27 page. Preserve the existing https://raw.githubusercontent.com/ultralytics/assets/main/yolov8/banner-yolov8.png image URL.

The artwork replacement shipped in ultralytics/assets#200, which updated the same shared asset, so the banner image already shows YOLO27 here and only the link still points at the previous campaign.

[UltralyticsAssistant]

👋 Hello @raimbekovm, thank you for submitting a ultralytics/.github 🚀 PR! This automated message confirms your contribution was received, and an Ultralytics engineer will assist with the review. To ensure a seamless integration of your work, please review the following checklist:

• ✅ Define a Purpose: Clearly explain the purpose of your fix or feature in your PR description, and link to any relevant issues. Ensure your commit messages are clear, concise, and adhere to the project's conventions.
• ✅ Synchronize with Source: Confirm your PR is synchronized with the ultralytics/.github main branch. If it's behind, update it by clicking the 'Update branch' button or by running git pull and git merge main locally.
• ✅ Ensure CI Checks Pass: Verify all Ultralytics Continuous Integration (CI) checks are passing. If any checks fail, please address the issues.
• ✅ Update Documentation: Update the relevant documentation for any new or modified features.
• ✅ Add Tests: If applicable, include or update tests to cover your changes, and confirm that all tests are passing.
• ✅ Sign the CLA: Please ensure you have signed our Contributor License Agreement if this is your first Ultralytics PR by writing "I have read the CLA Document and I sign the CLA" in a new message.
• ✅ Minimize Changes: Limit your changes to the minimum necessary for your bug fix or feature addition. "It is not daily increase but daily decrease, hack away the unessential. The closer to the source, the less wastage there is." — Bruce Lee

For more guidance, please refer to our Contributing Guide. Don't hesitate to leave a comment if you have any questions. Thank you for contributing to Ultralytics! 🚀

[UltralyticsAssistant]

🔍 PR Review

_{Made with ❤️ by Ultralytics Actions}

Reviewed the profile banner and destination URL change. The YOLO27 page exists, but the AVIF banner format is incompatible or unsupported by GitHub's external-image proxy path, so one rendering regression remains.

💬 Posted 1 inline comment

• 💡 MEDIUM profile/README.md:3 GitHub proxies externally hosted README images through Camo, whose supported image types do not include image/avif; GitHub's documentation also lists PNG, GIF, JPEG, and SVG as the supported image formats for all contexts. This can cause the new banner to render as a broken image on the organization profile even though the CDN URL is reachable. Please use a PNG or JPEG version of this asset instead. ([docs.github.com](https://docs.github.com/en/get-started/writing-on-github/working-with-advan…

[UltralyticsAssistant]

🔍 PR Review 2

_{Made with ❤️ by Ultralytics Actions}

Since the previous review, the banner image remains the requested PNG URL, resolving the prior format concern, while the destination link now points to the YOLO27 page. No remaining issues found. LGTM.