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

[renovate-bot]

This PR contains the following updates:

Package	Update	Change
com.google.guava:guava-bom	minor	28.1-android -> 28.2-android

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[codecov]

Codecov Report

Merging #42 into master will increase coverage by 1.41%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master      #42      +/-   ##
============================================
+ Coverage     77.56%   78.98%   +1.41%     
- Complexity       84       97      +13     
============================================
  Files             6        6              
  Lines           682      728      +46     
  Branches          2        2              
============================================
+ Hits            529      575      +46     
  Misses          151      151              
  Partials          2        2

Impacted Files	Coverage Δ	Complexity Δ
...ols/cloudbuild/v1/stub/CloudBuildStubSettings.java	83.77% <0%> (+0.21%)	26% <0%> (+1%)	⬆️
...evtools/cloudbuild/v1/stub/GrpcCloudBuildStub.java	95.27% <0%> (+0.55%)	18% <0%> (+1%)	⬆️
...cloud/devtools/cloudbuild/v1/CloudBuildClient.java	76.47% <0%> (+2.63%)	47% <0%> (+11%)	⬆️

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