fix: Broken links in README and Contributing Guidelines

[Dearxinxin]

Description

This PR fixes the broken links that previously pointed to opensauced.pizza.

What type of PR is this? (check all applicable)

• 🤝 Add a contributor
• 📝 Documentation Update

Related Issues

Closes #970

Contributors Checklist

I've read through the Getting Started section

• ✅ Yes
• ❌ Not yet

Have you run npm run contributors:generate to generate your profile and the badge on the README?

• ✅ Yes
• ❌ No

Added to documentation?

• 📜 README.md
• 🙅 no documentation needed

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[optional] What GIF best describes this PR or how it makes you feel?

[github-actions]

Congratulations on completing the How to Contribute to Open Source chapter of the Intro to Open Source Course with your contribution to this repository, @Dearxinxin! You're almost to the end of the course!

[adiati98]

@Dearxinxin thanks for your PR! ✨

Your PR title and description aren't match with the changes you made here. You need to update them accordingly so we can review your PR.

If you plan to add yourself to the guestbook, please create a separate new issue and PR.

[adiati98]

@Dearxinxin there's one small thing needs to fix here, then this is good to go.

[adiati98]

@Dearxinxin I've updated your PR title and description to follow your changes. Please see what I've changed there for your future reference.

If you want to add yourself to the guestbook, you can create a new PR.

Thanks for your contribution! ✨