feat: added github workflow to greet contributors

[Junaid-Mohamed]

What does this PR do?

This PR fixes the issue opened for a feature of greeting the contributors, during issue and PR opens.

Fixes #201

Type of change

• [x] New feature (non-breaking change which adds functionality)

How should this be tested?

For testing this you can open an test issue and the greet-contributors workflow will be triggered and expected outcome of github bot comment can be noticed in the issue.

Note : The owner of the repo can't do this testing, contributors can do it, since there is a check for owner in workflow, which when passes github bot comment won't be generated

Mandatory Tasks

• [x] Make sure you have self-reviewed the code. A decent size PR without self-review might be rejected.

Feel free to reach out through comments if you have any queries.

[github-actions[bot]]

Thank you for following the naming conventions! 🙏

[hemantwasthere]

@piyushgarg-dev Can you also review it once!