chore: regenerate README (googleapis#568)

This PR was generated using Autosynth. 🌈


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

```
2021-07-27 23:52:47,706 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 23:52:48,919 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

```
</details>

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https://source.cloud.google.com/results/invocations/c25e95ca-c298-4ce9-a71d-e75326d009e2/targets

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

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-resourcemanager.git",
-        "sha": "20441f5bd07ca8e55ccc352393ebb97727ea4bd0"
+        "sha": "c7d7e6244ad5fb6244bc6e88d2256e63fac42db2"
       }
     },
     {