fix: Increase MockVariableDebtToken contract revision to avoid bytecode clashes during verification

Author: miguelmtzinf

contracts/mocks/upgradeability/MockVariableDebtToken.sol

@@ -22,6 +22,6 @@ contract MockVariableDebtToken is VariableDebtToken {
   {}
 
   function getRevision() internal pure override returns (uint256) {
-    return 0x2;
+    return 0x3;
   }
 }