chore: Bump io.spring.dependency-management

Bumps the gradle-version-updates group in /backend with 1 update: [io.spring.dependency-management](https://github.com/spring-gradle-plugins/dependency-management-plugin).


Updates `io.spring.dependency-management` from 1.1.6 to 1.1.7
- [Release notes](https://github.com/spring-gradle-plugins/dependency-management-plugin/releases)
- [Commits](spring-gradle-plugins/dependency-management-plugin@v1.1.6...v1.1.7)

---
updated-dependencies:
- dependency-name: io.spring.dependency-management
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: gradle-version-updates
...

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

backend/build.gradle

@@ -2,7 +2,7 @@ plugins {
     id "java"
     id "idea"
     id "org.springframework.boot" version "3.4.0"
-    id "io.spring.dependency-management" version "1.1.6"
+    id "io.spring.dependency-management" version "1.1.7"
     id "io.freefair.lombok" version "8.11"
     id "com.github.spotbugs" version "6.0.26"
     id "com.github.ben-manes.versions" version "0.51.0"