Bump org.junit:junit-bom from 5.11.4 to 5.12.0

Bumps [org.junit:junit-bom](https://github.com/junit-team/junit5) from 5.11.4 to 5.12.0.
- [Release notes](https://github.com/junit-team/junit5/releases)
- [Commits](junit-team/junit5@r5.11.4...r5.12.0)

---
updated-dependencies:
- dependency-name: org.junit:junit-bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -4,7 +4,7 @@ embulk-util-rubytime = "0.4.0"
 
 joda-time = "2.13.1"
 
-junit5 = "5.11.4"
+junit5 = "5.12.0"
 
 checkstyle = "9.3"