[Diogo-Rego]

This MR updates the project's dependencies for GitHub Actions and the Nginx Docker image to ensure we are using the latest stable versions.

Changes

• GitHub Actions: Bumped actions/checkout from v6 to v7.
• Docker/Nginx: Bumped nginx/nginx-unprivileged from 1.31.2-trixie to 1.31.8-trixie in the /nginx directory.

Testing / Impact

• No breaking changes are expected.
• The CI/CD pipeline should run smoothly with the new checkout action.
• The Nginx container will use the updated trixie base image version.