fix(docker): update Debian repositories to archive for PHP 7.3 build

[pedrosanto90]

Description

The PHP 7.3.11-FPM image is based on Debian Buster, which has reached end-of-life and moved its repositories to the Debian archives.
Because of this, the default apt-get update failed due to invalid or missing release files.

This pull request updates the Dockerfile to point to the Debian archive repositories and disables the Acquire::Check-Valid-Until check, which is necessary because the package metadata for Debian Buster is no longer updated. Without this change, the build would continue to fail.

Task items:

• Updated Dockerfile to use archive.debian.org repositories;
• Disabled Acquire::Check-Valid-Until to allow using outdated package indexes;
• Verified successful Docker image build;
• Updated documentation if required;
• Other task related item;

Requirements (optional)

Requirements when deploying the current work to an environment (dev, staging or production):

• No database migrations required;
• No environment variables changed;
• No additional permissions required.

[quetzyg]

We should use the latest PHP version, instead.