I was eventually trying to run this code in remix IDE, where I was running this using 0.6.6 version of Solidity and ran into this error. I've tried using some other versions like 0.8 and 0.6 as well.
// SPDX-License-Identifier: MIT
pragma solidity =0.8.7;
import "@chainlink/contracts/src/v0.6/vendor/SafeMathChainlink.sol";
contract myContract{
using SafeMathChainlink for uint256;
mapping(address => uint256) public payTo;
function Payment() public payable {
uint256 minimumUSD = 50 * 10 ** 18;
require(getConversionRate(msg.value) >= minimumUSD, "Doesn't satisfy the minimum condition");
payTo[msg.sender] += msg.value;
}
}