Merge pull request ethereum#13151 from ethereum/setreleasedatefor0815

Set release date for 0.8.15.

Merge pull request ethereum#13034 from ethereum/setreleasedatefro0814

Set release date.

Merge pull request ethereum#12801 from ethereum/cse-optimization

CSE optimization

Merge pull request ethereum#12682 from ethereum/setreleasedatefor0812

Set release date.

Merge pull request ethereum#12426 from ethereum/setDateFor0811

Set release date for 0.8.11

Merge pull request ethereum#12255 from ethereum/setReleaseDate

Sort changelog and set release date.

Merge pull request ethereum#12056 from ethereum/setReleaseDatefro089

Set release date.

Merge pull request ethereum#12035 from ethereum/setReleaseDate

Set release date.

Merge pull request ethereum#11763 from ethereum/basefee-hasOpcode

Allow basefee as Yul identifier for EVMVersion < london

Merge pull request ethereum#11566 from ethereum/prepare086

Prepare release of 0.8.6.