deps: update dependency com.google.code.gson:gson to v2.8.8 (#1430)

Author: renovate-bot

pom.xml

@@ -577,7 +577,7 @@
     <project.appengine.version>1.9.71</project.appengine.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.jsr305.version>3.0.2</project.jsr305.version>
-    <project.gson.version>2.8.7</project.gson.version>
+    <project.gson.version>2.8.8</project.gson.version>
     <project.jackson-core2.version>2.12.4</project.jackson-core2.version>
     <project.protobuf-java.version>3.17.3</project.protobuf-java.version>
     <project.guava.version>30.1.1-android</project.guava.version>