chore: regenerate README (#202)

This PR was generated using Autosynth. 🌈


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

```
2020-12-10 18:37:14,938 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-notification/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2020-12-10 18:37:15,799 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/87d4ccbb-2117-4431-8251-91a271464bd7/targets

- [ ] To automatically regenerate this PR, check this box.

.github/readme/synth.metadata/synth.metadata

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-notification.git",
-        "sha": "e928ec9b883ca393de159ba40d4cf2dccea3f252"
+        "sha": "ba26c438d1573b539470b96b889e6a4e9825825f"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "7fcc405a579d5d53a726ff3da1b7c8c08f0f2d58"
+        "sha": "352f25621c28d2fa0784984ea0ed5ea697aa1525"
       }
     }
   ]

README.md

@@ -107,6 +107,8 @@ Java 8 OSX | [![Kokoro CI][kokoro-badge-image-3]][kokoro-badge-link-3]
 Java 8 Windows | [![Kokoro CI][kokoro-badge-image-4]][kokoro-badge-link-4]
 Java 11 | [![Kokoro CI][kokoro-badge-image-5]][kokoro-badge-link-5]
 
+Java is a registered trademark of Oracle and/or its affiliates.
+
 [product-docs]: 
 [javadocs]: https://googleapis.dev/java/google-cloud-notification/latest/index.html
 [kokoro-badge-image-1]: http://storage.googleapis.com/cloud-devrel-public/java/badges/java-notification/java7.svg