feat(forge): add support for Optimism Sepolia in "verify-contract"

[PierrickGT]

Component

Forge

Describe the feature you would like

Optimism has released a Sepolia test network: https://community.optimism.io/docs/useful-tools/networks/#op-sepolia

When running forge verify for this network, the following error is displayed:

error: invalid value 'optimism-sepolia' for '--chain <CHAIN>'
  [possible values: mainnet, morden, ropsten, rinkeby, goerli, kovan, holesky, sepolia, optimism, optimism-kovan, optimism-goerli, arbitrum, arbitrum-testnet, arbitrum-goerli, arbitrum-sepolia, arbitrum-nova, cronos, cronos-testnet, rsk, bsc, bsc-testnet, poa, sokol, scroll, scroll-alpha-testnet, metis, xdai, polygon, mumbai, polygon-zkevm, polygon-zkevm-testnet, fantom, fantom-testnet, moonbeam, moonbeam-dev, moonriver, moonbase, dev, anvil-hardhat, evmos, evmos-testnet, chiado, oasis, emerald, emerald-testnet, filecoin-mainnet, filecoin-calibration-testnet, avalanche, fuji, celo, celo-alfajores, celo-baklava, aurora, aurora-testnet, canto, canto-testnet, boba, base, base-goerli, linea, linea-testnet, zksync, zksync-testnet, mantle, mantle-testnet]

  tip: a similar value exists: 'optimism-goerli'

I have opened the following PR in the ether-rs repository to support Optimism Sepolia: gakonst/ethers-rs#2665
Once this PR merged and the package updated in foundry, we should be able to verify contracts on the Optimism Sepolia chain.

Additional context

No response