Bump maven-compiler-plugin from 3.8.1 to 3.9.0

Bumps [maven-compiler-plugin](https://github.com/apache/maven-compiler-plugin) from 3.8.1 to 3.9.0.
- [Release notes](https://github.com/apache/maven-compiler-plugin/releases)
- [Commits](apache/maven-compiler-plugin@maven-compiler-plugin-3.8.1...maven-compiler-plugin-3.9.0)

---
updated-dependencies:
- dependency-name: org.apache.maven.plugins:maven-compiler-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

pom.xml

@@ -23,7 +23,7 @@
         <junit.version>5.8.2</junit.version>
         <assertj.version>3.19.0</assertj.version>
         <!-- plugins -->
-        <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
+        <maven-compiler-plugin.version>3.9.0</maven-compiler-plugin.version>
         <maven-source-plugin.version>3.2.1</maven-source-plugin.version>
         <maven-javadoc-plugin.version>3.2.0</maven-javadoc-plugin.version>
         <maven-release-plugin.version>2.5.3</maven-release-plugin.version>