Bump assertj-core from 3.18.1 to 3.20.0

Bumps [assertj-core](https://github.com/assertj/assertj-core) from 3.18.1 to 3.20.0.
- [Release notes](https://github.com/assertj/assertj-core/releases)
- [Commits](assertj/assertj@assertj-core-3.18.1...assertj-core-3.20.0)

---
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>

javaparser-core-testing/pom.xml

@@ -118,7 +118,7 @@
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
-            <version>3.18.1</version>
+            <version>3.20.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>