Implement solidity 0.8 like v3-core and v3-periphery

[v3-core](https://github.com/Uniswap/v3-core/tree/0.8) and [v3-periphery](https://github.com/Uniswap/v3-periphery/tree/0.8) both expose solidity 0.8 implementation branches that can be installed easily in foundry(e.g. `forge install uniswap/v3-periphery@0.8`). I would like to install `forge install uniswap/v3-staker@0.8`