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

@@            Coverage Diff            @@
##             master     #173   +/-   ##
=========================================
  Coverage     78.29%   78.29%           
  Complexity      236      236           
=========================================
  Files             6        6           
  Lines          2216     2216           
  Branches         37       37           
=========================================
  Hits           1735     1735           
  Misses          432      432           
  Partials         49       49           

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