build(deps-dev): bump assertj-core from 3.14.0 to 3.15.0

Bumps [assertj-core](https://github.com/joel-costigliola/assertj-core) from 3.14.0 to 3.15.0.
- [Release notes](https://github.com/joel-costigliola/assertj-core/releases)
- [Commits](assertj/assertj@assertj-core-3.14.0...assertj-core-3.15.0)

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

Author: dependabot-preview[bot]

pom.xml

@@ -56,7 +56,7 @@
         <maven-surefire-plugin.version>2.22.2</maven-surefire-plugin.version>
         <junit.jupiter.version>5.5.2</junit.jupiter.version>
         <junit.platform.version>1.3.2</junit.platform.version>
-        <assertj-core.version>3.14.0</assertj-core.version>
+        <assertj-core.version>3.15.0</assertj-core.version>
     </properties>
 
     <dependencies>