feat[contracts]: have hardhat-deploy register L1MultiMessageRelayer on mainnet (#828)

* feat[contracts]: have deploy register multi message relayer on L1

* chore: add changeset

* fix: minor typo in comment

* fix: remove unnecessary changes

.changeset/tender-rings-deliver.md

+---
+'@eth-optimism/contracts': patch
+---
+
+Set L2MessageRelayer name to L1MultiMessageRelayer when deploying to mainnet

packages/contracts/deploy/014-OVM_L1MultiMessageRelayer.deploy.ts

@@ -5,6 +5,7 @@ import { DeployFunction } from 'hardhat-deploy/dist/types'
 import {
   deployAndRegister,
   getDeployedContract,
+  registerAddress,
 } from '../src/hardhat-deploy-ethers'
 
 const deployFn: DeployFunction = async (hre) => {
@@ -18,6 +19,20 @@ const deployFn: DeployFunction = async (hre) => {
     name: 'OVM_L1MultiMessageRelayer',
     args: [Lib_AddressManager.address],
   })
+
+  // OVM_L2MessageRelayer *must* be set to multi message relayer address on mainnet.
+  if (hre.network.name.includes('mainnet')) {
+    const OVM_L1MultiMessageRelayer = await getDeployedContract(
+      hre,
+      'OVM_L1MultiMessageRelayer'
+    )
+
+    await registerAddress({
+      hre,
+      name: 'OVM_L2MessageRelayer',
+      address: OVM_L1MultiMessageRelayer.address
+    })
+  }
 }
 
 deployFn.dependencies = ['Lib_AddressManager']