Add GhoUpgradeable audit report (#412)

Author: miguelmtzinf

README.md

@@ -46,6 +46,7 @@ You can find all audit reports under the [audits](./audits/) folder
 - [2023-10-23 - Sigma Prime (GHO Stability Module)](./audits/2023-10-23_GSM_SigmaPrime.pdf)
 - [2023-12-07 - Certora Formal Verification (GHO Stability Module)](./certora/reports/Formal_Verification_Report_of_GHO_Stability_Module.pdf)
 - [2024-03-14 - Certora Formal Verification (GhoStewardV2)](./audits/2024-03-14_GhoStewardV2_Certora.pdf)
+- [2024-06-11 - Certora Formal Verification (UpgradeableGHO)](./audits/2024-06-11_UpgradeableGHO_Certora.pdf)
 
 ## Getting Started