deps: update dependency com.google.protobuf:protobuf-java to v3.12.2

[renovate-bot]

This PR contains the following updates:

Package	Update	Change
com.google.protobuf:protobuf-java	patch	3.12.0 -> 3.12.2

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[codecov]

Codecov Report

Merging #72 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #72   +/-   ##
=========================================
  Coverage     75.48%   75.48%           
  Complexity       74       74           
=========================================
  Files             6        6           
  Lines           669      669           
  Branches          6        6           
=========================================
  Hits            505      505           
  Misses          156      156           
  Partials          8        8           

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