Added greetings.yml

[Kushal997-das]

For opening the issue and Pull request :
For opening issue message👇

It's great having you contribute to this project

Thanks for opening this Issue 🙌, Welcome to bhai-lang 💖 We will review everything and get back to you ! दयानन्द 🙌"


_For opening PR **message**👇_

It's great having you contribute to this project

Thank you for opening a Pull Request 🙌 , Welcome to bhai-lang 💖 We will review everything and get back to you ! दयानन्द 🙌"

_After every PR closed / merge **message**👇_
(@User_name) Hurray, your PR got merged 🥳. Thanks a bunch. Feel free to take another Issue.💖

[Kushal997-das]

@ristri @aniketsingh0104 Please review it , thanks :)