chore: regenerate README

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Log from Synthtool

2021-04-15 21:13:41,184 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigquerystorage/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-04-15 21:13:42,568 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

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[yoshi-approver]

Rubber stamped PR!

[codecov]

Codecov Report

Merging #1012 (6e15204) into master (cc243d9) will decrease coverage by 0.07%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #1012      +/-   ##
============================================
- Coverage     80.20%   80.13%   -0.08%     
  Complexity      710      710              
============================================
  Files            61       61              
  Lines          3961     3961              
  Branches        264      264              
============================================
- Hits           3177     3174       -3     
- Misses          660      663       +3     
  Partials        124      124              

Impacted Files	Coverage Δ	Complexity Δ
...e/cloud/bigquery/storage/v1beta2/StreamWriter.java	83.48% <0.00%> (-0.69%)	33.00% <0.00%> (ø%)

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