[Feature]: add github action workflow for greeting contributors

[harmeetsingh11]

Description: The current project lacks an automated action to greet contributors. GitHub Actions can significantly enhance project automation. I propose adding a GitHub Action workflow to greet new pull request (PR) and issue creators, fostering a welcoming environment.

Proposed Changes: Implement a GitHub Action workflow that triggers on new PRs and issues. The workflow should include a greeting message to acknowledge and appreciate the contributors for their efforts.

Expected Behavior: When contributors create new PRs or issues, the GitHub Action should automatically trigger and post a welcoming message, acknowledging their contributions.

Checklist

• [X] I have starred the repository
• [X] I have checked the existing issues
• [X] I am willing to work on this issue
• [X] I am an IWOC 2.0 contributor

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