Changed the link of the example report to the correct one (version 1.2.1)

Description

Changed the link to the example of checkup report, because it has changed after the release of the version 1.2.1 of postgres-checkup. The right link: https://gitlab.com/postgres-ai/postgres-checkup-tests/tree/master/1.2.1.

Related issue

[give full link to the related issue]

Examples

[present examples for reviewers: new CLI output, screenshots, etc]