Bump assertj-core from 3.19.0 to 3.21.0 (#39)

Bumps [assertj-core](https://github.com/assertj/assertj-core) from 3.19.0 to 3.21.0.
- [Release notes](https://github.com/assertj/assertj-core/releases)
- [Commits](https://github.com/assertj/assertj-core/compare/assertj-core-3.19.0...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>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pom.xml

@@ -20,7 +20,7 @@
         <lombok.version>1.18.22</lombok.version>
         <junit-jupiter.version>5.8.2</junit-jupiter.version>
         <mockito-junit-jupiter.version>4.2.0</mockito-junit-jupiter.version>
-        <assertj-core.version>3.19.0</assertj-core.version>
+        <assertj-core.version>3.21.0</assertj-core.version>
     </properties>
 
     <dependencies>