Remove Harry Potter gif from list of celebration gifs in auto merge workflow

Let's have some changes to celebrate queer pride month

🐞 Problem

We are using a Harry Potter gif to add to the comment after a pull request is successfully merged.

https://github.com/firstcontributions/first-contributions/blob/main/.github/workflows/auto-pr-merge.yml

             'https://media2.giphy.com/media/26gN16cJ6gy4LzZSw/giphy.gif',

Let's remove it.

💡 Future ideas

If you have some favourite celebration gifs, post them in comments below.

📋 Steps to solve the problem

• Comment below about what you've started working on.
• Add, commit, push your changes.
• Submit a pull request and add this in comments - Addresses #<put issue number here>
• Ask for reviews in comments section of pull request.
• Celebrate your contribution to this project. 🎉