chore: regenerate README

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Log from Synthtool

2021-02-26 01:24:30,042 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-billingbudgets/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-02-26 01:24:31,589 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

Full log will be available here:
https://source.cloud.google.com/results/invocations/049226ac-a447-49e2-8679-2057d17511b6/targets

• To automatically regenerate this PR, check this box.

[yoshi-approver]

Rubber stamped PR!

[codecov]

Codecov Report

Merging #408 (02e8f13) into master (8469e57) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #408   +/-   ##
=========================================
  Coverage     74.96%   74.96%           
  Complexity      107      107           
=========================================
  Files            12       12           
  Lines           775      775           
  Branches          6        6           
=========================================
  Hits            581      581           
  Misses          184      184           
  Partials         10       10           

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