Bump net.javacrumbs.shedlock:shedlock-core in /backend

Bumps [net.javacrumbs.shedlock:shedlock-core](https://github.com/lukas-krecan/ShedLock) from 4.42.0 to 6.0.1.
- [Changelog](https://github.com/lukas-krecan/ShedLock/blob/master/RELEASES.md)
- [Commits](lukas-krecan/ShedLock@shedlock-parent-4.42.0...shedlock-parent-6.0.1)

---
updated-dependencies:
- dependency-name: net.javacrumbs.shedlock:shedlock-core
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

backend/build.gradle

@@ -128,7 +128,7 @@ dependencies {
     implementation 'org.apache.commons:commons-lang3'
 
     // Shedlock for scheduler synchronization
-    implementation 'net.javacrumbs.shedlock:shedlock-core:4.42.0'
+    implementation 'net.javacrumbs.shedlock:shedlock-core:6.0.1'
     implementation 'net.javacrumbs.shedlock:shedlock-spring:5.12.0'
     implementation 'net.javacrumbs.shedlock:shedlock-provider-jdbc-template:5.12.0'