Type error with platform.deployContract

[ericglau]

When using platform.deployContract in typescript, a type error occurs.

Example:

import { ethers, platform } from "hardhat";

async function main() {
  const ContractFactory = await ethers.getContractFactory("MyToken");

  const instance = await platform.deployContract(ContractFactory);
  await instance.deployed();

  console.log(`Proxy deployed to ${instance.address}`);
}

cause type error:

Property 'deployContract' does not exist on type 'HardhatUpgrades'.