chore: regenerate README

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Log from Synthtool

2021-03-17 20:15:56,413 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-cloudbuild/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-03-17 20:15:57,353 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

Full log will be available here:
https://source.cloud.google.com/results/invocations/a40574ab-58ad-4040-8605-3f4dbf7c5ec3/targets

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[yoshi-approver]

Rubber stamped PR!

[codecov]

Codecov Report

Merging #430 (5ae8481) into master (b84e599) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #430   +/-   ##
=========================================
  Coverage     81.41%   81.41%           
  Complexity      104      104           
=========================================
  Files             6        6           
  Lines           888      888           
  Branches          3        3           
=========================================
  Hits            723      723           
  Misses          162      162           
  Partials          3        3           

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