Bump codecov-action to @v3

[rytilahti]

Fixes the following warning:

Node.js 12 actions are deprecated. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/. Please update the following actions to use Node.js 16: codecov/codecov-action@v2

[codecov-commenter]

Codecov Report

Merging #1643 (66beb92) into master (c3c845c) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1643   +/-   ##
=======================================
  Coverage   80.36%   80.36%           
=======================================
  Files         161      161           
  Lines       15988    15988           
  Branches     3607     3607           
=======================================
  Hits        12848    12848           
  Misses       2877     2877           
  Partials      263      263           

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