Update dependency protobuf to v3.20.3

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
protobuf	==3.20.2 -> ==3.20.3

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[codecov]

Codecov Report

Merging #332 (c162c38) into main (c08230e) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #332   +/-   ##
=======================================
  Coverage   63.47%   63.47%           
=======================================
  Files           2        2           
  Lines         115      115           
=======================================
  Hits           73       73           
  Misses         42       42           

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