feat: add github action workflow for greeting contributors

[harmeetsingh11]

Description

This PR closes issue: #384

Files added

• .github/workflows/auto-comment.yml

To run this workflow you need to enable the following permission:

1. Go to your codesetgo repository settings
2. On left pane > Actions > General

3. Scroll down and Go to Workflow permissions > select "Read and write permissions"

4. Click save and its done.

Please review this PR.
Thanks

[netlify]

✅ Deploy Preview for codesetgo ready!

Name	Link
🔨 Latest commit	eb4e8a3
🔍 Latest deploy log	https://app.netlify.com/sites/codesetgo/deploys/6489afa1e3ff990008874a73
😎 Deploy Preview	https://deploy-preview-417--codesetgo.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site settings.

[agamjotsingh18]

Checks isn't successful for auto comment, please check
Read and write permissions are already given

[harmeetsingh11]

I have tested the workflow for all events on my repository. Here are the screenshots: