Sort changelog and add release date for 0.8.25 (ethereum#14939)

Merge pull request ethereum#14810 from ethereum/set-changelog-for-8-2…

…4-release

Update changelog for 0.8.24 release

Merge pull request ethereum#14672 from ethereum/set-release-date-for-…

…0-8-23

Set date for 0.8.23 release

Merge pull request ethereum#14642 from ethereum/set-release-date-0.8.22

 Set release date for 0.8.22

Merge pull request ethereum#14427 from ethereum/set-release-date-vers…

…ion-0.8.21

Set release date for 0.8.21

Update bugs by version entry for 0.8.20.

Merge pull request ethereum#13996 from ethereum/set-release-date-for-…

…0.8.19

Set release date for 0.8.19

Merge pull request ethereum#13913 from ethereum/changelog-v0.8.18

Sort changelog for 0.8.18 alphabetically

Merge pull request ethereum#13502 from ethereum/finalize-release-0.8.17

Finalize release 0.8.17

Merge pull request ethereum#13358 from ethereum/set-release-date-0.8.16

Set release date for 0.8.16 and update the bug list