Add Auto-Assignment GitHub Action for Issues and PRs

[Varun-S10]

Add Auto-Assignment GitHub Action
This PR introduces a GitHub Actions workflow that automatically assigns new issues and pull requests to a designated team member. It ensures that every new task gets immediate ownership and avoid unassigned work items.

How It Works

1. Trigger Events

• The workflow runs whenever a new issue or pull request is opened.

2. Determine Assignees

• It has separate lists for issues and PRs
• The assignee is selected using round-robin logic based on the issue/PR number, so work is distributed consistently.

3. Automatic Assignment

• Once selected, the workflow assigns the issue/PR via the GitHub API.

Why This Is Needed

• Prevents new issues and PRs from being unassigned.
• Ensures even distribution of tasks among team members.
• Saves manual effort in assigning every new item.