deps: update dependency com.google.guava:guava-bom to v28.2-android

Author: renovate-bot

pom.xml

@@ -69,7 +69,7 @@
  <google.auth.version>0.19.0</google.auth.version>
  <gax.version>1.52.0</gax.version>
  <junit.version>4.12</junit.version>
- <guava.version>28.1-android</guava.version>
+ <guava.version>28.2-android</guava.version>
  <threeten.version>1.4.0</threeten.version>
  <animal-sniffer.version>1.18</animal-sniffer.version>
  <easymock.version>3.6</easymock.version>