Fixed a potentially dangerous link

[DakuwoN]

Fixes #6484

What changes did you make?

• Added noopener and noreferrer rel attribute to the anchor tag

Why did you make the changes (we will use this info to test)?

• For security purposes

Screenshots of Proposed Changes Of The Website (if any, please do not screen shot code changes)

No visible changes to the website.

[github-actions]

Want to review this pull request? Take a look at this documentation for a step by step guide!

From your project repository, check out a new branch and test the changes.

git checkout -b DakuwoN-unsafe-external-link-6484 gh-pages
git pull https://github.com/DakuwoN/website.git unsafe-external-link-6484

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Note that CONTRIBUTING.md cannot previewed locally; rather it should be previewed at this URL:

https://github.com/DakuwoN/website/blob/unsafe-external-link-6484/CONTRIBUTING.md  

[heejung-hong]

Good work!
The branches are correct and the issue is linked.
The correct file was changed with the correct information.
I have inspected and confirmed the changes in developer mode on Chrome (desktop, tablet, and mobile view), Firefox, and Safari browser.

Going forward, please delete the image example and indicate that there are no visible changes to the website.

[jphamtv]

Hey @DakuwoN - Thanks for working on this issue. Your summary of changes is clear and your code change is clean and accurate.

Great work!

[evan-ishibashi]

Code looks good and has been changed as requested. Nice!