Add GITHUB_USERNAME to environment variables and update extraction logic

[devanshjainms]

This pull request introduces a small but impactful change to make the script more dynamic by replacing a hardcoded GitHub username with a configurable environment variable. The changes ensure better reusability and adaptability for different users.

Environment Variable Update:

• demo/.env.example: Added a new GITHUB_USERNAME variable to the example environment file to allow users to specify their GitHub username.

Code Update for Dynamic Username:

• demo/extract_github_data.py: Updated the main() function to load the GITHUB_USERNAME value from the environment and replaced the hardcoded username "jennifermarsman" with the github_username variable for filtering repositories. [1] [2]

[jennifermarsman]

@devanshjainms Hi, thanks for your contribution! I'm taking some time off after Build so please forgive the delay in response, but I will be back in the office next week and will take a look at this then.