Bump com.google.code.gson:gson from 2.2.4 to 2.8.9

Bumps [com.google.code.gson:gson](https://github.com/google/gson) from 2.2.4 to 2.8.9.
- [Release notes](https://github.com/google/gson/releases)
- [Changelog](https://github.com/google/gson/blob/main/CHANGELOG.md)
- [Commits](google/gson@gson-2.2.4...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]>

pom.xml

@@ -63,7 +63,7 @@
   <properties>
     <commons.lang.version>2.5</commons.lang.version>
     <slf4j.version>1.7.5</slf4j.version>
-    <gson.version>2.2.4</gson.version>
+    <gson.version>2.8.9</gson.version>
     <guava.version>13.0.1</guava.version>
     <junit.version>4.11</junit.version>
     <cdap.common.version>0.12.0</cdap.common.version>