Solidity - v0.8.6

Solidity 0.8.6 fixes some non-critical but annoying bugs, especially a warning about unreachable code that
is in fact reachable.

For more details, please see the release announcement.

Language Features:
* Yul: Special meaning of ".metadata" data object in Yul object.

Bugfixes:
* Control Flow Graph: Fix incorrectly reported unreachable code.
* Solc-Js: When running solcjs without the --optimize flag, use settings.optimizer.enabled=false in Standard JSON instead of omitting the key.
* Standard JSON: Omitting settings.optimizer.enabled was not equivalent to setting it to false. It meant disabling also the peephole optimizer and jumpdest remover which by default still run with enabled=false.

We especially thank all the contributors that made this release possible:
Alex Beregszaszi, Allegheny Crypto, axeldelamarre, Djordje Mijovic, hrkrshnn, jgoodall628, Kamil Śliwak, Leonardo, Mathias Baumann, patekuru, QQ喵, TaldenV

If you want to perform a source build, please only use solidity_0.8.6.tar.gz and not the zip provided by github directly.