build(deps): bump gson from 2.9.0 to 2.9.1

Bumps [gson](https://github.com/google/gson) from 2.9.0 to 2.9.1.
- [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-2.9.0...gson-parent-2.9.1)

---
updated-dependencies:
- dependency-name: com.google.code.gson:gson
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/pom.xml b/pom.xml
index 1659fdb..44aa405 100644
--- a/pom.xml
+++ b/pom.xml
@@ -129,7 +129,7 @@
     <equalsverifier.version>3.10.1</equalsverifier.version>
     <freemarker.version>2.3.31</freemarker.version>
     <groovy.version>3.0.12</groovy.version>
-    <gson.version>2.9.0</gson.version>
+    <gson.version>2.9.1</gson.version>
     <guava.version>31.1-jre</guava.version>
     <hamcrest.version>2.2</hamcrest.version>
     <httpclient.version>4.5.13</httpclient.version>