automate more parts of the publishing process

[gabrielittner]

With this it is not neccessary to push commits to main anymore to do a release and as much as possible is automated. The remaining steps are:

1. update changelog (through a pr), we could probably also have some automation here but I personally don't like these auto generated changelogs
2. create and push a tag for the new version

To make this possible there are a few changes:

• slightly updated the CHANGELOG.md format
• the release workflow will extract the section for the new release and automatically create a Github release with it
• VERSION_NAME is not comitted anymore and instead always computed
• for releases we tag the tag name as version
• for snapshots we take the last tag increment the last number by 1 and then append SNAPSHOT
• the readme contains <latest-version> pacehoders and one of those badges that shows the last version
• for the website we automatically replace <latest-version> with the last tag and remove the badge
• snapshot and website workflows run after the release so that there is a snapshot for the next release and the website contains the latest version

The only part that I don't like that much is the <latest-version> placeholder in the README, I prefer when it just has the full declaration ready to copy, but at least it's like this on the website.

Already tested this here

[kboyarshinov]

Nice 👍

[kboyarshinov]

awk 🤯

[gabrielittner]

Got it from stack overflow 😆