chore: regenerate README (#486)
chore: regenerate README (#486)

This PR was generated using Autosynth. :rainbow:


<details><summary>Log from Synthtool</summary>

```
2021-08-31 16:32:47,322 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigqueryreservation/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-31 16:32:48,753 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

```
</details>

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https://source.cloud.google.com/results/invocations/127de764-8d5f-48be-a707-75639a5d31bd/targets

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