fix: remove invalid 'enabled: auto' from jreleaser prerelease config

JReleaser 1.19.0 fails with:
"Cannot deserialize value of type java.lang.Boolean from String 'auto':
only 'true' or 'false' recognized"

The prerelease.enabled field expects a boolean value, not 'auto'.
Removed the enabled field entirely and kept only the pattern field,
which determines if a release is marked as prerelease based on
version matching.

Updated pattern to match common prerelease patterns:
- RC (Release Candidate)
- SNAPSHOT
- M (Milestone)
- alpha
- beta

This allows JReleaser to automatically determine prerelease status
based on the version string pattern matching.

Author: bsbodden

jreleaser.yml

@@ -24,8 +24,7 @@ release:
     overwrite: true
     sign: true
     prerelease:
-      enabled: auto
-      pattern: .*-SNAPSHOT.*
+      pattern: .*-(RC|SNAPSHOT|M|alpha|beta).*
     draft: false
     changelog:
       formatted: ALWAYS