docs: add note about the limitation in Rekor

[developer-guy]

Signed-off-by: Batuhan Apaydın batuhan.apaydin@trendyol.com

Description

This PR aims to add information about the limitation in Rekor about the attestation size.

Related issues

• Close #XXX

Related PRs

sigstore/rekor#1313
aquasecurity/trivy-plugin-attest#6

Remove this section if you don't have related PRs.

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).

[itaysk]

Thanks! LGTM. leaving for @knqyf263 for merging
If you want to make the warning more prominent, feel free to replace > with !!! note https://squidfunk.github.io/mkdocs-material/reference/admonitions/
we use this annotation extensively also in this file

[knqyf263]

Thanks👍