Update example-usdc-cctp.mdx (axelarnetwork#1265)

Co-authored-by: Idris Olubisi <[email protected]>

Author: BahadorGh

src/content/docs/dev/general-message-passing/developer-guides/example-usdc-cctp.mdx

@@ -29,8 +29,10 @@ CrosschainNativeSwap.sol
 // SPDX-License-Identifier: MIT
 pragma solidity 0.8.9;
 
+import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
 import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import {AxelarExecutable} from "@axelar-network/axelar-gmp-sdk-solidity/contracts/executable/AxelarExecutable.sol";
 import {ITokenMessenger} from "./ITokenMessenger.sol";
 
 contract CrosschainNativeSwap is AxelarExecutable, Ownable {