Bump gson from 2.8.1 to 2.8.6 (iluwatar#1147)

Bumps [gson](https://github.com/google/gson) from 2.8.1 to 2.8.6.
- [Release notes](https://github.com/google/gson/releases)
- [Changelog](https://github.com/google/gson/blob/master/CHANGELOG.md)
- [Commits](google/gson@gson-parent-2.8.1...gson-parent-2.8.6)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

event-sourcing/pom.xml

@@ -43,7 +43,7 @@
     <dependency>
       <groupId>com.google.code.gson</groupId>
       <artifactId>gson</artifactId>
-      <version>2.8.1</version>
+      <version>2.8.6</version>
     </dependency>
 
   </dependencies>