Updates optimism dependencies (Synthetixio#1308)

* Updated optimism deps

* Update usage of dep in code

* Add hardhat-ethers dep required by smock

* Add await in unit test

Author: eternauta1337

hardhat.config.js

@@ -5,6 +5,7 @@ const path = require('path');
 
 require('./hardhat');
 require('@nomiclabs/hardhat-truffle5');
+require('@nomiclabs/hardhat-ethers');
 require('solidity-coverage');
 require('hardhat-gas-reporter');
 

hardhat/tasks/task-compile.js

@@ -25,7 +25,7 @@ task('compile')
 		if (taskArguments.useOvm) {
 			console.log(gray('Compiling with OVM Solidity compiler...'));
 
-			require('@eth-optimism/plugins/hardhat/compiler');
+			require('@eth-optimism/hardhat-ovm');
 			hre.config.ignoreNonOvmContracts = true;
 		}