Switch to main branch based development

[dbast]

Reasons:

• shortens the development process
• ci + linting workflows allow to keep the quality up and potentially do a minor/major release after every PR merge to main... so there won't be that many un-released changes waiting in the main branch, that maybe confuse users as a tagged=releases version behave differently to what the current README says (which happened in the past).
• enables better usage of dependabot, as it analyses the repo default branch (main) and then doing PRs against develop would often fail if that deviates.
• more in line in regards to how other popular actions are devloped (like https://github.com/actions/checkout or https://github.com/actions/cache or https://github.com/docker/build-push-action)