Update dependency org.junit.jupiter:junit-jupiter to v6

Author: renovate[bot]

gradle/libs.versions.toml

@@ -5,7 +5,7 @@ commons-compress = "1.28.0"
 commons-io = "2.22.0"
 commons-lang = "3.20.0"
 json = "20251224"
-junit-jupiter = "5.14.4"
+junit-jupiter = "6.1.0"
 netty = "4.2.13.Final"
 oci-registry = "0.7.0"
 reactor-kotlin = "1.3.0"