feat: add hardhat deploy instructions to readme (#965)

* feat: add deployment instructions to readme

* Add changeset

* fix style

* Update README.md

.changeset/late-countries-guess.md

+---
+'@eth-optimism/contracts': patch
+---
+
+Update contracts README to add deploy instructions.

packages/contracts/README.md

@@ -84,5 +84,81 @@ You can also build specific components as follows:
 yarn build:contracts
 ```
 
+### Deploying the Contracts
+To deploy the contracts first clone, install, and build the contracts package.
+
+Next set the following env vars:
+
+```bash
+CONTRACTS_TARGET_NETWORK=...
+CONTRACTS_DEPLOYER_KEY=...
+CONTRACTS_RPC_URL=...
+```
+
+Then to perform the actual deployment run:
+
+```bash
+npx hardhat deploy \
+  --network ... \  # `network` MUST equal your env var `CONTRACTS_TARGET_NETWORK`
+  --ovm-address-manager-owner ... \
+  --ovm-proposer-address ... \
+  --ovm-relayer-address ... \
+  --ovm-sequencer-address ... \
+  --scc-fraud-proof-window ... \
+  --scc-sequencer-publish-window ...
+```
+
+This will deploy the contracts to the network specified in your env and create
+an artifacts directory in `./deployments`.
+
+To view all deployment options run:
+
+```bash
+npx hardhat deploy --help
+
+Hardhat version 2.2.1
+
+Usage: hardhat [GLOBAL OPTIONS] deploy [--ctc-force-inclusion-period-seconds <INT>] [--ctc-max-transaction-gas-limit <INT>] --deploy-scripts <STRING> [--em-max-gas-per-queue-per-epoch <INT>] [--em-max-transaction-gas-limit <INT>] [--em-min-transaction-gas-limit <INT>] [--em-ovm-chain-id <INT>] [--em-seconds-per-epoch <INT>] --export <STRING> --export-all <STRING> --gasprice <STRING> [--l1-block-time-seconds <INT>] [--no-compile] [--no-impersonation] --ovm-address-manager-owner <STRING> --ovm-proposer-address <STRING> --ovm-relayer-address <STRING> --ovm-sequencer-address <STRING> [--reset] [--scc-fraud-proof-window <INT>] [--scc-sequencer-publish-window <INT>] [--silent] --tags <STRING> [--watch] --write <BOOLEAN>
+
+OPTIONS:
+
+  --ctc-force-inclusion-period-seconds  Number of seconds that the sequencer has to include transactions before the L1 queue. (default: 2592000)
+  --ctc-max-transaction-gas-limit       Max gas limit for L1 queue transactions. (default: 9000000)
+  --deploy-scripts                      override deploy script folder path
+  --em-max-gas-per-queue-per-epoch      Maximum gas allowed in a given queue for each epoch. (default: 250000000)
+  --em-max-transaction-gas-limit        Maximum allowed transaction gas limit. (default: 9000000)
+  --em-min-transaction-gas-limit        Minimum allowed transaction gas limit. (default: 50000)
+  --em-ovm-chain-id                     Chain ID for the L2 network. (default: 420)
+  --em-seconds-per-epoch                Number of seconds in each epoch. (default: 0)
+  --export                              export current network deployments
+  --export-all                          export all deployments into one file
+  --gasprice                            gas price to use for transactions
+  --l1-block-time-seconds               Number of seconds on average between every L1 block. (default: 15)
+  --no-compile                          disable pre compilation
+  --no-impersonation                    do not impersonate unknown accounts
+  --ovm-address-manager-owner           Address that will own the Lib_AddressManager. Must be provided or this deployment will fail.
+  --ovm-proposer-address                Address of the account that will propose state roots. Must be provided or this deployment will fail.
+  --ovm-relayer-address                 Address of the message relayer. Must be provided or this deployment will fail.
+  --ovm-sequencer-address               Address of the sequencer. Must be provided or this deployment will fail.
+  --reset                               whether to delete deployments files first
+  --scc-fraud-proof-window              Number of seconds until a transaction is considered finalized. (default: 604800)
+  --scc-sequencer-publish-window        Number of seconds that the sequencer is exclusively allowed to post state roots. (default: 1800)
+  --silent                              whether to remove log
+  --tags                                specify which deploy script to execute via tags, separated by commas
+  --watch                               redeploy on every change of contract or deploy script
+  --write                               whether to write deployments to file
+
+deploy: Deploy contracts
+
+For global options help run: hardhat help
+```
+
+### Verifying Deployments on Etherscan
+If you are using a network which Etherscan supports you can verify your contracts with:
+
+```bash
+npx hardhat etherscan-verify --api-key ... --network ...
+```
+
 ## Security
 Please refer to our [Security Policy](https://github.com/ethereum-optimism/.github/security/policy) for information about how to disclose security issues with this code.