deps: update dependency com.google.code.gson:gson to v2.8.7 (#370)

Author: renovate-bot

java-shared-dependencies/pom.xml

@@ -65,7 +65,7 @@
  <google.auth.version>0.25.5</google.auth.version>
  <google.http-client.version>1.39.2</google.http-client.version>
  <google.api-client.version>1.31.5</google.api-client.version>
- <gson.version>2.8.6</gson.version>
+ <gson.version>2.8.7</gson.version>
  <threeten.version>1.5.1</threeten.version>
  <javax.annotations.version>1.3.2</javax.annotations.version>
  <animal-sniffer.version>1.20</animal-sniffer.version>