[Feature]: Add GitHub Workflows for Greetings, Auto-Labeling, and PR Merge Notifications

[samyak-aditya]

Description:
To enhance repository automation and streamline contributor engagement, let's add GitHub workflows for greeting new contributors, auto-labeling pull requests, and notifying contributors on successful PR merges.

Proposed Workflows:

1. Greetings Workflow: Automatically welcome new contributors with a personalized message on their first issue or PR, encouraging them to contribute further.
2. Auto-Labeling Workflow: Configure a workflow to apply labels based on PR or issue content, making it easier to categorize and manage tasks.
3. PR Merge Notification: Add a workflow to send a notification to contributors when a pull request is successfully merged, keeping them informed of project updates.

Benefits:
These workflows will improve contributor experience, enhance project organization, and ensure that all contributors stay informed, contributing to a smoother collaboration process.

hey @StephCurry07 Please assign me this Task with label "level3"

[github-actions]

👋 Thank you @samyak-aditya for raising an issue! We appreciate your effort in helping us improve. Our team will review it shortly. Stay tuned!