Add CI Pipeline for automated testing

[qu35t-code]

Description

This update introduces a Continuous Integration (CI) pipeline using GitHub Actions, providing automated testing and package installation for the repository. The new workflow triggers on pushes and pull requests to the main branch, ensuring that code changes are tested consistently.

The pipeline includes several steps :

• Checkout Code: Clones the repository to access the source code.
• Set Up Python: Configures Python 3.11 as the runtime environment.
• Install System Dependencies: Installs the required system dependencies.
• Install Dependencies from Source: Upgrades pip and installs the required dependencies listed in requirements.txt.
• Execute Test Command from Source: Runs the script and checks its usage output to validate functionality.

This CI setup enhances the project's reliability by automating testing and verifying that installations work as intended, making it easier to maintain code quality and catch issues early in the development process.

Here is a test example : https://github.com/QU35T-code/lightyear/actions/runs/11667618274

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Note : lxml does not seem to be compatible with python version 3.12 / 3.13, so the CI uses the latest compatible version: 3.11 -> https://github.com/QU35T-code/lightyear/actions/runs/11667472469