feat: add `OptimismMintableFiatTokenV2_2` for compatibility with `IOptimismMintableERC20`

[alvrs]

Context:

• Optimism's L2StandardBridge expects the IOptimismMintableERC20 interface on ERC20 tokens being bridged from L1 to L2
  • Docs: https://docs.optimism.io/builders/app-developers/bridging/standard-bridge#bridged-tokens
  • Relevant piece of code in the bridge: https://github.com/ethereum-optimism/optimism/blob/develop/packages/contracts-bedrock/src/universal/StandardBridge.sol#L267

For normal ERC20 tokens we could use Optimism's ERC20 factory, but for USDC we need to follow the Bridged USDC Standard in order to have the option to eventually migrate the contract to a native Circle issued USDC, instead of ending up with two USDC variants on the L2.