Bump io.micronaut.test:micronaut-test-junit5 in /java (#323)

Bumps [io.micronaut.test:micronaut-test-junit5](https://github.com/micronaut-projects/micronaut-test) from 4.7.0 to 4.8.1.
- [Release notes](https://github.com/micronaut-projects/micronaut-test/releases)
- [Commits](micronaut-projects/micronaut-test@v4.7.0...v4.8.1)

---
updated-dependencies:
- dependency-name: io.micronaut.test:micronaut-test-junit5
  dependency-version: 4.8.1
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

java/micronaut-server/pom.xml

@@ -94,7 +94,7 @@
     <!-- Micronaut properties -->
     <micronaut.runtime>netty</micronaut.runtime>
     <micronaut.version>${project.parent.version}</micronaut.version>
-    <micronaut.test.version>4.7.0</micronaut.test.version>
+    <micronaut.test.version>4.8.1</micronaut.test.version>
     <micronaut.gql.version>4.7.0</micronaut.gql.version>
 
     <!-- Native image properties -->