docs: reference audit files from previous osx versions (#39)

* docs: added audit files from previous osx versions

* refactor: just reference the audit

* docs: improved explanation

README.md

@@ -2,6 +2,36 @@
 
 OSX-Commons: A collection of shared resources and utilities for the Aragon OSX DAO Framework, including subgraph, contract, and SDK functionalities.
 
+## Audits
+
+Our smart contracts undergo regular audits.
+
+### v1.0.0
+
+_Version `1.0.0` of `osx-commons-contracts` has been audit when it was part of the `aragon/osx` repo._
+
+**Halborn**: [link 1](./audits/Halborn_AragonOSx_2023-02-24.pdf), [link 2](https://github.com/HalbornSecurity/PublicReports/blob/b3fe424535dce7ce345f74dc7e6c25e9200e7860/Solidity%20Smart%20Contract%20Audits/Aragon_aragonOS_Smart_Contract_Security_Audit_Report_Halborn_Final.pdf)
+
+- Commit ID: [cb0621dc5185a73240a6ca33fccc7698f059fdf5](https://github.com/aragon/osx/commit/cb0621dc5185a73240a6ca33fccc7698f059fdf5)
+- Started: 2023-02-07
+- Finished: 2023-02-24
+
+### v1.3.0
+
+_Version `1.3.0` of `osx-commons-contracts` has been audit when it was part of the `aragon/osx` repo._
+
+**Code4rena**: [link 1](./audits/Code4rena_AragonOSx_2023-12-12.pdf), [link 2](https://code4rena.com/reports/2023-03-aragon)
+
+- Commit ID: [a2461ae61a8c4cc833a117120b76e306936f5e1c](https://github.com/aragon/osx/commit/a2461ae61a8c4cc833a117120b76e306936f5e1c)
+- Started: 2023-03-03
+- Finished: 2023-03-10
+
+**Halborn**: [link 1](./audits/Halborn_AragonOSx_2023-06-13.pdf), [link 2](https://github.com/HalbornSecurity/PublicReports/blob/b3fe424535dce7ce345f74dc7e6c25e9200e7860/Solidity%20Smart%20Contract%20Audits/Aragon_aragonOS_v1_3_0_Smart_Contract_Security_Assessment_Report_Halborn_Final.pdf)
+
+- Commit ID: [0ad8cad2bb661fbd53086d097d11228304d9b73e](https://github.com/aragon/osx/commit/0ad8cad2bb661fbd53086d097d11228304d9b73e)
+- Started: 2023-05-29
+- Finished: 2023-06-13
+
 ## Contributing
 
 If you like what we're doing and would love to support, please review our `CONTRIBUTING_GUIDE.md` [here](https://github.com/aragon/osx/blob/develop/CONTRIBUTION_GUIDE.md). We'd love to build with you.