chore(deps): bump com.github.luben:zstd-jni in /backend

Bumps [com.github.luben:zstd-jni](https://github.com/luben/zstd-jni) from 1.5.6-5 to 1.5.6-6.
- [Commits](luben/zstd-jni@v1.5.6-5...v1.5.6-6)

---
updated-dependencies:
- dependency-name: com.github.luben:zstd-jni
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

backend/build.gradle

@@ -50,7 +50,7 @@ dependencies {
     implementation "org.springframework.boot:spring-boot-starter-security"
 
     implementation 'org.apache.commons:commons-compress:1.27.1'
-    implementation 'com.github.luben:zstd-jni:1.5.6-5'
+    implementation 'com.github.luben:zstd-jni:1.5.6-6'
     implementation 'org.tukaani:xz:1.10'
 
     implementation("org.redundent:kotlin-xml-builder:1.9.1")