feat(misconf): add metadata to Cloud schema

[nikpivkin]

Description

The schema was missing a metadata type.

Related PRs

• refactor(checks): migrate from Go to Rego trivy-checks#131

Checklist

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• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
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[simar7]

The change seems fine to me but what if a user tried to use new checks (downloaded a new bundle) that reference this schema but didn't have this schema (was using older version of trivy with old schema)? Would we still be able to fallback to the embedded version?

[nikpivkin]

If Trivy still contains built-in checks that do not reference the new schema, then yes, they will be used.