Upgraded protoc version to latest

[mhutchinson]

Checklist

• I have updated the CHANGELOG.
  • Adjust the draft version number according to semantic versioning rules.
• I have updated documentation accordingly (including the feature implementation matrix).

[codecov]

Codecov Report

Merging #2088 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2088   +/-   ##
=======================================
  Coverage   58.92%   58.92%           
=======================================
  Files         115      115           
  Lines        9778     9778           
=======================================
  Hits         5762     5762           
  Misses       3513     3513           
  Partials      503      503           

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[mhutchinson]

@pavelkalinnikov I've made the upgrade change in this PR too. Are you happy with this?

This didn't have the effect I expected, but at least it rules something out about why the docs are being generated with diffs in #2087, and this seems like a good thing to keep updated too.

I'll squash the commits in this PR together when merging.

[pav-kv]

LGTM.