Bump gson from 2.2 to 2.8.9

Bumps [gson](https://github.com/google/gson) from 2.2 to 2.8.9.
- [Release notes](https://github.com/google/gson/releases)
- [Changelog](https://github.com/google/gson/blob/master/CHANGELOG.md)
- [Commits](google/gson@gson-2.2...gson-parent-2.8.9)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pom.xml

@@ -111,7 +111,7 @@
     <freemarker.version>2.3.29</freemarker.version>
     <!-- gitlab4j-api 4.10.15 Switched to the jakarta version of the activation and servlet dependencies. -->
     <gitlab4j-api.version>4.10.14</gitlab4j-api.version>
-    <google-gson.version>2.2</google-gson.version>
+    <google-gson.version>2.8.9</google-gson.version>
     <google-guava.version>19.0</google-guava.version>
     <google-zxing-javase.version>3.0.0</google-zxing-javase.version>
     <googlecode-json-simple.version>1.1.1</googlecode-json-simple.version>