chore: regenerate README (#666)
chore: regenerate README (#666)

This PR was generated using Autosynth. :rainbow:


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

```
2021-07-29 17:58:33,314 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-language/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-07-29 17:58:34,616 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

```
</details>

Full log will be available here:
https://source.cloud.google.com/results/invocations/1a7e2b6e-6eac-41e2-814d-3ff251440e16/targets

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