chore(docs): update docusaurus

[ludofischer]

Update docusaurus to latest release.
Seem mostly layout fixes https://github.com/facebook/docusaurus/releases/tag/v2.0.0-beta.1

[codecov-commenter]

Codecov Report

Merging #1151 (b91addf) into master (1a9bd4b) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1151   +/-   ##
=======================================
  Coverage   96.43%   96.43%           
=======================================
  Files         116      116           
  Lines        3592     3592           
  Branches     1054     1054           
=======================================
  Hits         3464     3464           
  Misses        119      119           
  Partials        9        9           

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