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

@@            Coverage Diff            @@
##             master      #65   +/-   ##
=========================================
  Coverage     59.30%   59.30%           
  Complexity       26       26           
=========================================
  Files             6        6           
  Lines           172      172           
  Branches          1        1           
=========================================
  Hits            102      102           
  Misses           69       69           
  Partials          1        1           

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