Fix HTTP to HTTPS in Tutorial Endpoints

[antoniamaia]

Description

The tutorial currently uses http in the API endpoint examples, which should be updated to https to reflect the correct and secure URL.

This issue aims to:

• Replace all instances of http:// with https:// in the tutorial.
• Ensure consistency across all documentation and examples.
• Prevent confusion for users trying to access the API using the correct protocol.

Example to update

endpoints:
  - name: snippets-api
    path: http://demo.scanapi.dev/api/v1/

Should become

endpoints:
  - name: snippets-api
    path: https://demo.scanapi.dev/api/v1/