deps: update dependency com.google.code.gson:gson to v2.8.6 (#833)

Author: renovate-bot

pom.xml

@@ -553,7 +553,7 @@
     <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>2.8.5</project.gson.version>
+    <project.gson.version>2.8.6</project.gson.version>
     <project.jackson-core2.version>2.10.0</project.jackson-core2.version>
     <project.protobuf-java.version>3.10.0</project.protobuf-java.version>
     <project.guava.version>28.1-android</project.guava.version>