Bump gson from 2.8.6 to 2.8.9 in /freemarker-generator-maven-plugin

Bumps [gson](https://github.com/google/gson) from 2.8.6 to 2.8.9.
- [Release notes](https://github.com/google/gson/releases)
- [Changelog](https://github.com/google/gson/blob/master/CHANGELOG.md)
- [Commits](https://github.com/google/gson/compare/gson-parent-2.8.6...gson-parent-2.8.9)

---
updated-dependencies:
- dependency-name: com.google.code.gson:gson
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/freemarker-generator-maven-plugin/pom.xml b/freemarker-generator-maven-plugin/pom.xml
index c8b014a..d7d640f 100644
--- a/freemarker-generator-maven-plugin/pom.xml
+++ b/freemarker-generator-maven-plugin/pom.xml
@@ -35,7 +35,7 @@
         <maven-core.version>3.6.3</maven-core.version>
         <maven-plugin-api.version>3.6.3</maven-plugin-api.version>
         <maven-plugin-annotations.version>3.6.0</maven-plugin-annotations.version>
-        <gson.version>2.8.6</gson.version>
+        <gson.version>2.8.9</gson.version>
         <mockito.version>3.7.7</mockito.version>
         <assertj-core.version>3.18.1</assertj-core.version>
     </properties>