Stick to JUnit 5.x

JUnit 6 requires Java 17.

Author: acogoluegnes

.github/dependabot.yml

@@ -10,6 +10,8 @@ updates:
     ignore:
       - dependency-name: "org.springframework.boot:spring-boot-maven-plugin"
         versions: ["[3.0,)"]
+      - dependency-name: "org.junit:*"
+        versions: [ "[6.0,)" ]
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule: