Added /greet endpoint to EmployeeController

[Anushree-001]

Pull Request Template

Description

This PR adds a new /greet GET endpoint in the EmployeeController class inside the employee-manager project.

It returns a simple greeting message:
"Hello from Keploy Java Sample!"

This is a new non-breaking feature added for learning and open-source contribution as part of the internship task.

Type of change

New feature (non-breaking change which adds functionality)

Please delete options that are not relevant.

How Has This Been Tested?

The /greet endpoint was tested locally using Postman and the browser to confirm it returns the expected message:
"Hello from Keploy Java Sample!"

The server started without errors and no existing functionality was affected.

Additional Context (Please include any Screenshots/gifs if relevant)

This was added as part of the Keploy Open Source Contribution Task.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have checked my code and corrected any misspellings

[pratik-mahalle]

Hey @Anushree-001, Thank you for raising the pr. The changes look good before that please make sure to sign the DCO