Bump gson from 2.8.8 to 2.8.9 (#335)

Bumps [gson](https://github.com/google/gson) from 2.8.8 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-parent-2.8.8...gson-parent-2.8.9)

---
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>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

problem-gson/pom.xml

@@ -10,7 +10,7 @@
     </parent>
     <artifactId>problem-gson</artifactId>
     <properties>
-        <gson.version>2.8.8</gson.version>
+        <gson.version>2.8.9</gson.version>
     </properties>
     <dependencies>
         <dependency>