Update contribute.md

[BTANISHA11]

I want to add some sections in contribute.md:

1. How to contribute
2. How to create an issue
3. How to create a new branch
   Pls assign this to me @crazycodigo

[Jayanti2919]

The first point is already addressed.

If you want to document how GitHub issues and PRs work, you can make a separate markdown for that. (github.md for example)

[BTANISHA11]

@Jayanti2919 so basically in github.md i need to specify how to make a PR AND CREATE AN ISSUE

[KhushiiAgarwal]

Please assign me this issue