Bump assertj-core from 3.20.2 to 3.21.0

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:development
  update-type: version-update:semver-minor
...

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

pom.xml

@@ -172,7 +172,7 @@
       <dependency>
         <groupId>org.assertj</groupId>
         <artifactId>assertj-core</artifactId>
-        <version>3.20.2</version><!-- Java 7 -->
+        <version>3.21.0</version><!-- Java 7 -->
       </dependency>
     </dependencies>
   </dependencyManagement>