Fix Greece examples

[cavalle]

Describe your changes

Greece examples weren't up-to-date with recent changes.

This PR also updates the suppliers tax ID to use the one pre-registered in the sandbox environment of the ILYDA app.

Checklist before requesting a review

• I have performed a self-review of my code.
• [N/A] I have added thorough tests with at least 90% code coverage.
• I've modified or created example GOBL documents the show my changes in use, if appropriate.
• [N/A] When adding or modifying a tax regime or addon, I've added links to the source of the changes either structured or in the comments.
• [N/A] I've run go generate . to ensure that Schemas and Regime data are up to date.
• [N/A] All linter warnings have been reviewed and fixed.
• [N/A] I've been obsessive with pointer nil checks to avoid panics.
• [N/A] The CHANGELOG.md has been updated with an overview of my changes.
• Requested a review from @samlown.