[FEAT] Improve VERSION file management

[nieomylnieja]

Is your feature request related to a problem? Please describe.

Currently sloctl maintainers have to manually increment VERSION file before each release. It's a step that's easy to miss/forget.

Describe the solution you'd like

I see two solutions:

• Automate the VERSION file incrementing (harder).
  • Automating this during each push, security wise, would be rather unwanted changed. We'd have to commit directly to main.
  • Maybe the best/only viable solution is to commit to PR branches on each PR?
• Drop and error if VERSION file is not incremented during release (easier).