Add audit reports (#1615)

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## Overview
Adds audit reports from Informal Systems and Binary Builders.

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## Checklist

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- [ ] New and updated code has appropriate documentation
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## Summary by CodeRabbit


- **Documentation**
- Updated the README.md with audit information including dates,
auditors, versions, and report links.

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Author: Manav-Aggarwal

README.md

@@ -147,3 +147,11 @@ Graph](https://github.com/rollkit/rollkit/blob/main/specs/src/specs/rollkit-depe
 ## Code of Conduct
 
 See our Code of Conduct [here](https://docs.celestia.org/community/coc).
+
+## Audits
+
+| Date       | Auditor                                       | Version                                                                             | Report                                                  |
+|------------|-----------------------------------------------|-------------------------------------------------------------------------------------|---------------------------------------------------------|
+| 2024/01/12  | [Informal Systems](https://informal.systems/) | [eccdd...bcb9d](https://github.com/rollkit/rollkit/commit/eccdd0f1793a5ac532011ef4d896de9e0d8bcb9d)   | [informal-systems.pdf](specs/audit/informal-systems.pdf) |
+| 2024/01/10 | [Binary Builders](https://binary.builders/)   | [eccdd...bcb9d](https://github.com/rollkit/rollkit/commit/eccdd0f1793a5ac532011ef4d896de9e0d8bcb9d) | [binary-builders.pdf](specs/audit/binary-builders.pdf)   |
+