Bump assertj-core from 3.20.2 to 3.21.0 in /modules/junit-jupiter

Bumps [assertj-core](https://github.com/assertj/assertj-core) from 3.20.2 to 3.21.0.
- [Release notes](https://github.com/assertj/assertj-core/releases)
- [Commits](assertj/assertj@assertj-core-3.20.2...assertj-core-3.21.0)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

modules/junit-jupiter/build.gradle

@@ -12,7 +12,7 @@ dependencies {
     testImplementation ('org.mockito:mockito-core:3.12.4') {
         exclude(module: 'hamcrest-core')
     }
-    testImplementation 'org.assertj:assertj-core:3.20.2'
+    testImplementation 'org.assertj:assertj-core:3.21.0'
     testImplementation 'org.junit.jupiter:junit-jupiter-params:5.7.2'
 
     testRuntimeOnly 'org.postgresql:postgresql:42.2.23'