Bump javersVersion from 6.12.0 to 6.13.0

Bumps `javersVersion` from 6.12.0 to 6.13.0.

Updates `org.javers:javers-spring-boot-starter-sql` from 6.12.0 to 6.13.0
- [Release notes](https://github.com/javers/javers/releases)
- [Commits](javers/javers@javers-6.12.0...javers-6.13.0)

Updates `org.javers:javers-core` from 6.12.0 to 6.13.0
- [Release notes](https://github.com/javers/javers/releases)
- [Commits](javers/javers@javers-6.12.0...javers-6.13.0)

---
updated-dependencies:
- dependency-name: org.javers:javers-spring-boot-starter-sql
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.javers:javers-core
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle

@@ -17,7 +17,7 @@ group = 'edu.kit.datamanager'
 ext {
     // versions of dependencies
     springDocVersion  = '1.6.15'
-    javersVersion     = '6.12.0'
+    javersVersion     = '6.13.0'
     keycloakVersion   = '19.0.0'
 
     // directory for generated code snippets during tests