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

@@ -42,7 +42,7 @@
     <oauth2-oidc-sdk.version>9.9</oauth2-oidc-sdk.version>
     <hibernate-validator.version>6.2.0.Final</hibernate-validator.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <assertj.version>3.20.2</assertj.version>
+    <assertj.version>3.21.0</assertj.version>
     <junit.version>5.8.1</junit.version>
     <apache-httpclient.version>5.1</apache-httpclient.version>
     <maven-deploy-plugin.version>2.8.2</maven-deploy-plugin.version>