Bump com.gradleup.shadow from 8.3.6 to 9.4.2

Bumps [com.gradleup.shadow](https://github.com/GradleUp/shadow) from 8.3.6 to 9.4.2.
- [Release notes](https://github.com/GradleUp/shadow/releases)
- [Commits](GradleUp/shadow@8.3.6...9.4.2)

---
updated-dependencies:
- dependency-name: com.gradleup.shadow
  dependency-version: 9.4.2
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

backend/build.gradle.kts

@@ -1,5 +1,5 @@
 plugins {
-    id("com.gradleup.shadow") version "8.3.6"
+    id("com.gradleup.shadow") version "9.4.2"
     id("io.micronaut.application") version "4.5.0"
 }