add changelog file

[vincanger]

[Martinsos]

Hm what would be the process around it? We could, for every "release" we do, add changes from the last one to the Changelog.
One option is also to stick to the process where each PR has to add info about itself to CHangelog. Although, you cuold say people can then just go and check the list of PRs on Github hm.

[Martinsos]

Some extra motivation for this: https://discord.com/channels/686873244791210014/920312576133443634/1328281113277497354 .

What I get from this exchange is that it would be valuable if we listed bigger changes we did in each iteration of OpenSaas, e.g. in the ChangeLog.md, so people can see if there was some bug fix for example -> then they can react to that and also do the fix on their side. These would also be part of each release note. Kind of like we do for wasp.