docs: Updated JSON schema version 2 in the trivy documentation

[amitverse]

Description

Since, Trivy Open Source is currently using schema version 2 as discueed here. But even after migrating to new change, the documentation still contains an example which shows result in older schema version 1.
This PR addresses the JSON schema version change to 2 in Trivy documentaion. With the changes made in this PR, the trivy documentation page is showing example in updated schema version.

Related issues

• Close #7553

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).