chore: regenerate README (googleapis#559)

This PR was generated using Autosynth. 🌈


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

```
2021-07-27 22:10:29,933 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-resourcemanager/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-07-27 22:10:31,226 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/d7c31e6b-5360-4869-8cef-99a7edea2dd0/targets

- [ ] To automatically regenerate this PR, check this box. (May take up to 24 hours.)

java-resourcemanager/.github/readme/synth.metadata/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-resourcemanager.git",
-        "sha": "6a81d66f4861c50d5e9b29ee4f0181222f8fa978"
+        "sha": "5dbd8f335b6a01054c608aa539b3cedcc287d3e6"
       }
     },
     {