Pre-releases

Set prerelease: beta to publish 1.3.0-beta.1, 1.3.0-beta.2, …

prerelease: beta

• A new pre-release is only proposed when a releasable commit happened since the previous one.
• Removing the option graduates to the stable version (1.3.0) with the changelog covering everything since the last stable release.
• The bump level is always computed from the commits since the last stable tag; the changelog starts at the last tag (of any kind) while in pre-release mode.
• On GitHub, releases are flagged as pre-release. GitLab releases have no such flag, so the hint is only used on GitHub.
• Partial version markers are left unchanged for pre-releases, because no floating tag exists for them.

Step	Version
feat: after v1.2.0 with beta	1.3.0-beta.1
another fix:	1.3.0-beta.2
remove prerelease and run relwolf	1.3.0