Create CONTRIBUTING.md

[debnath003]

Added CONTRIBUTING.md

Brief Summary of Changes

Added CONTRIBUTING.md, which will help the contributors with contributing guidelines for this repository!

What does this PR address?

• [x] GitHub issue (Add reference - #339)
• [ ] Refactoring
• [ ] New feature
• [ ] Bug fix
• [ ] Adds more tests

Are tests included?

• [ ] Yes
• [x] No

Reviewer, please note:

Checklist:

• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I ran the full test suite before pushing the changes and all the tests pass.