An upgradeable token.

MyToken.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20BurnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/AccessControlUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

contract MyToken is Initializable, ERC20Upgradeable, ERC20BurnableUpgradeable, AccessControlUpgradeable, OwnableUpgradeable {
    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");

    function initialize() public initializer {
        __ERC20_init("MyToken", "TOK");
        __Ownable_init();
        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
        _grantRole(MINTER_ROLE, msg.sender);
        _mint(msg.sender, 100000 * 10 ** decimals());
    }

    function mint(address to, uint256 amount) public onlyRole(MINTER_ROLE) {
        _mint(to, amount);
    }
}